Image source, Reuters

We're pausing our live coverage of the war in Ukraine now - but we'll leave you with a roundup of what happened today.

Nato summit in Madrid

• Leaders of countries in the Western military alliance Nato have branded Russia a "direct threat" to their security and pledged to strengthen their support for Ukraine
• The alliance's chief Jens Stoltenberg said the number of Nato troops placed on high alert should increase to 300,000 "by next year"

• Stoltenberg also confirmed that Finland and Sweden are being formally invited to join the military group

• Poland has welcomed a decision by the United States to make permanent its army base there
• The UK, too, has pledged to toughen its military presence in Eastern Europe

In Ukraine

• President Zelensky has cut diplomatic ties with Syria after it joined Russia in formally recognising the "independence" of two Moscow-backed separatist regions

• Ukraine says it has carried out the biggest prisoner swap with Russia since the war started. 144 soldiers have been exchanged from each side.

• Relatives continue to search for their loved ones after Monday's missile strike on a shopping centre in Kremenchuk which killed at least 18 people

Today's live coverage was brought to you by Marita Maloney, Sam Hancock, James Harness, Tori Lindrea, Catherine Evans, James FitzGerald, Claire Heald, Claudia Allen, Heather Sharp and Chris Giles.

Image source, Ukrainian Presidency

Ukraine's President Zelensky has announced the end of diplomatic relations with Syria, blaming a move from Damascus to officially recognised two Russian-backed, self-declared republics of Donetsk and Luhansk in eastern Ukraine as being independent.

It's the first country to do so other than Russia, its staunch ally.

Zelensky described the move as a "worthless story".

Image source, Getty Images

The Biden administration is supporting the sale of F-16 fighter jets to Turkey, saying it will help boost Nato's security.

It comes a day after Ankara lifted its opposition to Nato membership for Finland and Sweden.

Turkey made a request in October to the United States to buy 40 F-16 aircraft and nearly 80 kits to modernise its existing warplanes.

"The United States supports Turkey’s modernisation of its fighter fleet because that is a contribution to Nato security and therefore American security," Assistant Secretary for Defense for International Security Affairs Celeste Wallander said in a briefing reported by Reuters.

She said the plans for the sale were "in the works" and "need to be worked through our contracting processes".

But US officials rejected any suggestion of a link between the sale and Turkey's agreement to drop its objection to the two Nordic nations' Nato membership.

"The US did not offer anything to Turkey and was not asked for anything by Turkey” as part of its agreement with Finland and Sweden, Reuters cited a senior administration official as saying.

Congress will have the final say about the sales.

Chris Partridge
BBC News

Image source, Raytheon Technologies

President Zelensky has been asking for advanced Western missile defence systems for months and it now looks like it could happen.

Reports suggest the US has bought the Raytheon & Kongsberg-developed National Advanced Surface to Air Missile System (NASAMS) for Ukraine.

In the US, such a system already protects the White House and US Capitol and it’s used by other countries including Norway, Finland, Spain and Lithuania.

Ukraine wants to boost its defences against attacks from Russian aircraft and cruise missiles, the latter of which caused such devastation and loss of life at the Kremenchuk shopping centre on Monday.

NASAMS is a medium to long-range system used to take down aircraft and cruise missiles. The system is relatively easy to use, is mobile and delivers a networked capability for Ukraine.

It uses the tried-and-tested AIM-120 AMRAAM, whose air-to-air variant is used by the F-22, F-35, F-16 and F/A-18 aircraft.

Fired from ground-based launchers, they feature active radar tracking, high resistance to electronic countermeasures and are said to be 90% effective.

In use, a missile would be initially guided to the target by ground-based radar, then at a certain point the AMRAAM’s onboard radar activates to deliver terminal guidance.

Ukraine has been using older Soviet-built systems, such as the S-300 long-range missile and the shorter range Buk-M1 (SA-11) units. They’re effective, but modern systems offer more.

Very short-range protection continues to be provided by Western-supplied Manpads (portable air-defence systems) such as the Stinger and Starstreak.

Image source, Reuters

Russia's President Putin has given his reaction to the news that Finland and Sweden are to be officially invited to join Nato.

He has consistently opposed the expansion of the 30-member military alliance.

Putin says he does not rule out fresh tensions with the two Nordic nations, according to quotes carried by Russian news agencies.

He adds that Moscow will respond in kind if Nato infrastructure is deployed to Finland and Sweden.

As for the fighting in Ukraine itself, Putin is quoted saying his ultimate goal is to "liberate" the entire eastern Donbas region.

Commenting on Monday's missile strike on a shopping centre in Kremenchuk, Putin says that Russia does not hit civilian targets.

Polish President Andrzej Duda has welcomed news that the United States is planning to establish a permanent army base in his country.

“I’m satisfied because today I feel in a strong way that our security is being boosted,” he told the BBC’s Kasia Madera in an exclusive interview at the Nato summit in Madrid.

Duda went on to describe this as a “sad satisfaction” – saying that his warnings over the threat posed by Russia before its invasion of Ukraine had fallen on deaf ears.

Image source, Reuters

We mentioned earlier that the US has announced an expanded military presence for American forces across Europe, following Russia's invasion of Ukraine.

Here's a little more detail about the US plans.

President Biden earlier told the Nato summit that his country will create a new permanent army headquarters in Poland.

Previously, American troops were there on a rotating basis.

Other new deployments across the continent will see fighter jet squadrons sent to the UK, troops rotating in Romania, air defence units sent to Germany and Italy, and two more warships taken to Spain.

Biden echoed the words of other Nato leaders by saying Russia's President Putin had got "exactly what he didn't want" - having ordered his invasion of Ukraine in an effort to stop Nato expanding.

Jonathan Beale
BBC defence correspondent

Image source, Getty Images

Britain and the US say they will strengthen their military presence in Nato and to the defence of Eastern Europe in response to the threat posed by Russia.

The UK will increase the numbers of troops ready to deploy to the region as well as warships and fighter jets.

The Ministry of Defence (MOD) says it’s significantly increasing the availability of forces to Nato’s collective defence.

It says that will mean more warships, fighter jets and land forces on standby – though the MOD says it’s not giving details on numbers – because it's “militarily sensitive”.

The commitment follows an announcement at the Nato summit to dramatically expand the size of the alliances quick reaction force - from 40,000 to 300,000 military personnel. While some of these forces will be forward deployed, most will remain on standby.

Britain’s already nearly doubled the size of its military presence in Estonia – with just over 1,600 troops there.

About 1,000 more troops will be allocated to the defence of the Baltics – the equivalent overall of a combat brigade. However, the MOD says these additional troops may be held at high readiness back home.

The commitments being made at the Nato summit are clearly designed to send a clear message to Russia.

But while Britain is promising to make more of its troops, warships and fighter jets available, it won’t alter the size of Britain’s smaller armed forces – or its commitments elsewhere.

Sophie Williams
Reporting from Kremenchuk

Image source, Getty Images

Kremenchuk's prosecution office says it's launched a criminal investigation amid reports that the shopping centre’s management had told staff to remain open during air raid sirens.

It's been reported that staff had been told of the new policy just four days before the strike.

Previously the mall had closed during air raid sirens, one person told the BBC.

Dariya Kokhanovska, whose mother is missing, told the BBC that her mother’s shop stopped closing during air alerts.

The management told Forbes that they are not commenting on the claims while an internal and external investigation is underway.

Image source, Getty Images

More now on the prisoner swap that appears to have taken place between the warring sides today.

Earlier we reported that Ukraine had said it had received 144 soldiers from Russia, many of them with serious injuries.

Now, the head of Russia-backed rebel fighters in Ukraine's Donetsk region has said that his forces were involved in the swap.

Writing on Telegram, Denis Pushilin, head of the self-proclaimed Donetsk People's Republic said: "Today we are returning home 144 fighters of the Donetsk People's Republic and the Russian Federation who had been captured by the enemy.

"We handed over to Kyiv as many prisoners from the armed formations of Ukraine, the majority of whom are wounded."

Pushilin said several of the freed Ukrainian prisoners of war were members of "nationalist battalions" who had severe injuries, such as limb amputations.

Sophie Williams
Reporting from Kremenchuk

Image source, EPA

As we mentioned earlier, relatives are still searching for their loved ones following the missile strike on Kremenchuk.

Svitlana Rybalko, the press officer for Kremenchuk Emergency Services has confirmed to the BBC that 36 people are missing and some 18 people have died.

President Zelensky predicted that as many as 1,000 people could have been inside the building at the time.

One survivor of the attack on the shopping mall described the moment he managed to escape.

"I saw people lying around, some weren't responding. The fire was getting bigger and I was walking on glass," he said.

Frank Gardner
BBC News Security Correspondent, reporting from Madrid

Nato’s updated Strategic Concept explains, in an 11-page document, external, how the alliance views the threats facing western democracies and how it plans to deal with them.

Gone are the past mealy-mouthed references to Russia or China being partners.

The Russian Federation, it says, is the most significant and direct threat to allies’ security and to peace and stability in the Euro-Atlantic area. We cannot consider it to be our partner but we remain willing to keep open channels of communication to prevent escalation, it says.

China’s malicious hybrid and cyber operations and its confrontational rhetoric harm alliance security, the document says, and the deepening strategic partnership between Russia and China runs counter to Nato values and interests.

In reference to President Putin’s repeated reminders that he’s got a large arsenal of nuclear weapons, Nato’s Strategic Concept points to its own formidable nuclear deterrent.

If anyone used nuclear weapons against the alliance, it says, then it has the capabilities and resolve to impose "unacceptable" costs on an adversary. But these circumstances, it adds, are "extremely remote".

The Strategic Concept is short on detail of where Nato plans to place its reinforcements.

But its door remains open to new members, it says, and in words that will further annoy the Kremlin: we will continue to develop our partnerships with Bosnia and Herzegovina, Georgia and Ukraine.

Image source, Getty Images

US President Joe Biden has thanked the Turkish leader Recep Tayyip Erdogan for dropping his opposition to the entry of Finland and Sweden into Nato.

The path was cleared for the two Nordic nations to join the bloc after an announcement yesterday that they’d reached a security agreement with Turkey – the only country in the alliance that was proving resistant.

Biden added Turkey was doing "incredible work" in trying to get grain out of Ukraine and Russia.

President Erdogan said it was a "joy" to meet with Biden again.

Russian President Vladimir Putin still wants to take most of Ukraine, says the US director of national intelligence.

Avril Haines said Russian forces are so "degraded" they may take years to recover - but the situation in Ukraine remains "pretty grim".

Haines expects Putin's military to rely on cyber attacks, efforts to control energy and even nuclear weapons to project power.

Adam Easton
Warsaw Correspondent

Image source, Getty Images

Poland’s deputy foreign minister has welcomed a US decision to make its military presence in the country permanent.

Earlier, at the Nato summit in Madrid, President Joe Biden announced that the US 5th Corp command headquarters in Poznan, western Poland, would become permanent.

It will be the first time Nato or US troops are stationed permanently in the country – previously deployments have always been on a persistent rotational basis.

“Something that seemed impossible to many is becoming a fact today. We have a permanent presence in Poland. We care about our common security. It is also a clear signal to Moscow,” Marcin Przydacz wrote on Twitter.

Poland has long called for the US military deployment in the country to be changed from rotational to permanent.

The US 5th Corps Command headquarters was set up in Poznan in November 2020. Its 200 staff conduct operational planning, mission command and oversight of the US land forces in Europe.

Military analysts say the decision to make the HQ permanent will mean an increase in its staff to around 700.

There are about 4,500 US troops serving with Nato on a persistent rotational basis in north eastern Poland, and Washington has also temporarily deployed an additional 4,700 soldiers to Rzeszow in south-eastern Poland - not far from the Ukraine border.

Image source, Reuters

Thank you for joining our live coverage of the war in Ukraine and the Nato defence alliance's summit in Madrid.

Read on for a little refresher of what's been going on today.

Nato summit

• Leaders from the alliance declared Russia a “direct threat” to their security and pledged to keep supporting Ukraine
• Nato chief Jens Stoltenberg said a plan to raise the number of troops on high alert to 300,000 should happen "by next year"
• The secretary-general earlier confirmed Nato would formally invite Finland and Sweden to come on board, after Turkey dropped its objections
• As Nato pledged to boost its support for Ukraine, the US announced it would make its army HQ in Poland permanent

In Ukraine

• Kyiv has hailed the “largest” prisoner swap of the war so far – saying it received 144 soldiers from Russia, many with serious injuries
• At least three people have died after a Russian missile strike on a residential building in the southern city of Mykolaiv; Russia claims it hit a training base for “foreign mercenaries”
• Indonesian President Joko Widodo has visited Kyiv in an effort to restart peace talks between Ukraine and Russia

Chris Mason
Political editor

Not many years ago, there were stark and public criticisms of Nato, from its own members.

Donald Trump, when US president-elect, called the military alliance "obsolete". President Macron of France labelled it "brain dead".

But there's a vitality born of necessity here - a collection of countries confronted by an aggressive Russia, awoken from an era of shrivelling defence budgets after the end of the Cold War.

The British prime minister has told us repeatedly of his pride in the UK being the biggest defence spender in Europe.

But the public bristling about the adequacy or otherwise of the budget from the defence secretary and the head of the armed forces mirrors private concerns in parliament and beyond about what's seen as creative accounting.

As prices spiral, money goes less far; a manifesto commitment to ensure the growth of defence spending outstripped inflation every year has been broken. And the headcount in the army is falling.

It is also true the UK's contribution to Nato outstrips that of many of its other members - as this alliance faces up to a dangerous future, and a clamour for the money to match.

More from Boris Johnson now who says the UK has increased its defence budget "massively" since the end of the Cold War.

He says in 2021 the UK was the third biggest defence spender in the world, and this year the UK's spending is at 2.3% of GDP which is above the 2% commitment made to Nato. He says these are long-term spending commitments.

Johnson says he would like "partners" to recognise that everybody needs to "step up to the plate".

UK Prime Minister Boris Johnson has been speaking at the Nato summit in Madrid.

He is asked about reports that the UK is earmarking 1,000 extra troops for eastern Europe, external.

He doesn't confirm any details of troop numbers, but says "we're moving support to that area", and "we're moving away from trip-wire response to continuous enhanced forward presence".

Johnson goes on to say the UK is offering Baltic nations "long-term support; partnership to help them build up their forces and make sure they can repel any attack immediately".

Asked whether Nato is assuming that we are entering a second Cold War, Stoltenberg says Nato has strived for better relations with Russia for decades.

He says Russia was invited to participate in many activities, and considered a strategic partner of Nato in 2010, but "it's Russia that walked away" from attempts to build partnership.

It has done that with a pattern of behaviour - using force against Georgia, annexing Crimea and using force in the Donbas in eastern Ukraine from 2014, he says.

Nato's relationship with Russia is at the lowest level since the end of the Cold War, he says, but there is no doubt that the responsibility for that is from Russia.

He says Nato members and other like-minded countries want to reach out to countries that are "not as like-minded", but "we can't be naive" and there is a need to ensure there's no risk of any military action against a Nato country.