The World Health Organization says it is still unable to get desperately needed medical supplies into the besieged southern town of Mariupol, and also Mykolaiv, which is further west on the Black Sea.

Tarik Jasarevic, of the WHO, has just arrived in the central-eastern city of Dnipro, and told the BBC the UN health agency is setting up a staging post to move supplies, but has not been able to reach the two areas.

The WHO says it has verified 64 attacks on healthcare up to 21 March. Jasarevic said this hospitals, medical centres and ambulances had been hit.

He said such attacks have "a devastating effect on everyone".

Health workers don’t feel safe doing their jobs, patients are afraid to seek treatment, and immunisation programmes, care for chronic disease such as diabetes and cancer, and maternity care were all affected, he said.

If healthcare is not protected "the community will just basically be terrified, knowing that there are no more humanitarian boundaries to the war and there is no safe place," he said.

Image source, Reuters

Image source, EPA

More on Europe's continuing purchases of Russian energy - EU chief Ursula von der Leyen says Russia will no longer be able to use energy to blackmail the continent.

The European Commission president said Russia would not be allowed to demand payment in roubles for its oil and gas, as Moscow has announced, as this would amount to circumventing sanctions.

"This would be a unilateral decision and a clear breach of contract," she said.

"It would be an attempt to circumvent the sanctions. We will not allow our sanctions to be circumvented. The time when energy could be used to blackmail us is over."

Earlier German Chancellor Olaf Scholz also refused to pay for energy in roubles, saying that the currency for payments had already been specified in contracts.

No indication sanctions are working yetpublished at 18:37 Greenwich Mean Time 24 March 2022

18:37 GMT 24 March 2022

Nick Beake
BBC News, Brussels

Despite the proclamations ringing out here at Nato HQ - support for Ukraine and a determination to punish Russia financially - I’ve just had a sobering insight from one Western official who was in the leaders’ meeting earlier.

Apparently, not one leader could give any indication that sanctions had begun to change Putin's mind or affect his behaviour in his war on Ukraine.

The Nato strategy depends on supplying the Ukrainians with weapons while waiting for the unprecedented financial penalties levied on Russia to persuade him to stop attacking his neighbour.

But for millions of Ukrainians - displaced, under fire and sleeping in bunkers for a month - it is the most terrifying of waits. More civilians will die as the war grinds on.

Nato figures insist publicly and behind the scenes that they’re doing all they can to arm Ukraine, while not escalating the conflict or becoming directly involved - which, they say, could have dire consequences.

But I’m reminded of the young family I met exactly a month ago, deep under the streets of Kyiv in the shelter of a metro station just after Russia had launched its attack.

Alexander cradling his young son asked: “Where are Nato to help us?”

Many Ukrainians want much more support from their powerful Western friends, and they want it now.

Russia's foreign ministry has been reacting to today's Nato summit.

It says the decision to continue support to Kyiv shows that the Western alliance wants the conflict to continue, in a statement reported by Russia's Ria news agency.

The West was "reaping a terrible harvest" from its decision to arm Ukraine, which had encouraged the Ukrainian government to use force against Russian-backed separatist enclaves in eastern Ukraine, the ministry said.

Russia has previously said that people in the separatist enclaves were facing "genocide".

Image source, Reuters

Here’s a quick summary of the main points as the US President Joe Biden addressed the media from the Nato summit in Brussels.

• The US is announcing new sanctions on more than 400 individuals and entities, including more than 300 members of the Russian Duma, oligarchs and defence companies
• Nato has never been more united, which is the opposite of what President Putin expected to happen
• If Russia were to use chemical weapons, the US would respond, and “the nature of response will depend on the nature of the use"
• Biden said he had made clear to Chinese President Xi Jinping that he would be putting his economic relations with the US and EU in “significant jeopardy” if he were to help Russia
• The US president said he would like to see Russia removed from the G20, but if that’s not possible, Ukraine should attend as an observer
• He stressed that Western countries must stay "totally, thoroughly united"

Biden ends his news conference with a call for Western countries to maintain a united front towards Russia.

Asked whether sanctions would deter Putin, he says the most important thing is that they be sustained.

"The maintenance of sanctions - increasing the pain - to be sure that after a month we will sustain what we are doing. That's what will stop him," he says.

"The single most important thing is for us to stay unified and for the world to focus on what a brute he is.

"if you're Putin and you think Europe is going to crack in a month - they can take anything for a month - we have to stay totally, thoroughly united."

US President Joe Biden is asked if he has seen any indication of action - or lack of action - from China that has led him to believe they will help Russian forces.

Biden replies he’s made it clear to China’s president the consequences of him helping Russia.

He says he made “no threats” but pointed out the number of US and foreign corporations that have left Russia as a consequence of their “barbaric behaviour”.

He says China would be putting their economic relations with Europe and the US in “significant jeopardy” if they were to move forward.

Biden has been asked twice about the potential use of chemical weapons by Russia in Ukraine and what the Nato and US response would be.

In his first reply he says the nature of the response would depend on the nature of the use of chemical weapons.

Pressed on whether it would trigger direct Nato intervention in Ukraine, he says it would "trigger a response in kind".

"On Nato, we'd make that decision at the time," he says.

Image source, EPA

Biden says the US is determined to sustain its efforts with its allies on Ukraine.

He said the US was announcing new sanctions on 400 Russian individuals and entities, including 300 members of the Duma - Russia's parliament - as well as oligarchs and companies that "fuel the Russian war machine".

And he says Putin badly miscalculated in his decision to invade Ukraine.

"Putin was banking on Nato being split. From my conversations with him it was clear he didn't think it could sustain this cohesion," he says

"Putin is getting exactly the opposite of what he thought he was going to get when he went into Ukraine.

"Nato has never been more united than it is today."

US President Joe Biden has begun his media briefing.

Stay with us for live updates.

Image source, EPA

Here's a quick summary of the UK prime minister's key messages in his press conference at the emergency Nato summit in Brussels:

• The UK will ramp up lethal aid to Ukraine “at scale” in order to help President Zelensky to defend his country from its “bullying neighbour”
• The UK will send 6,000 more missiles and £25m in unrestricted funding for Ukraine's armed forces
• There will be a new deployment of UK troops to Bulgaria, on top of a doubling of UK troops both in Poland and in Estonia
• Nato and the G7 are united in their determination to wean themselves off Russian oil and gas
• The UK PM again ruled out a no-fly zone over Ukraine - saying it would involve the RAF taking down Russian fast jets
• Johnson said he was “not remotely anti-Russian” and was sympathetic to the Russian people, but not Vladimir Putin
• Talk about the use of nuclear weapons is a distraction, the use of conventional weapons in Ukraine is "absolutely barbaric"
• He said he believes President Putin understands the use of chemical weapons by Russia would be "catastrophic for him"

Johnson is asked about Nato chief Jens Stoltenberg saying earlier that there would be severe consequences if Russia uses chemical weapons in Ukraine and does that mean boots on the ground?

The PM says those weapons are viewed with “utter horror” by Nato leaders.

He says if Putin were to engage in anything like that “the consequences would be very, very severe”.

You have to have a bit of ambiguity about your response, he adds - but it would be “catastrophic for him” and “I think he understands that”.

Responding to a question from Bloomberg, Johnson says talk about the use of nuclear weapons is a distraction from what is going on in Ukraine.

He says the use of conventional weapons by Russia - including artillery - is "absolutely barbaric".

Moscow is trying to frame this as a confrontation between nuclear powers, he says - but it is between Russia and the people of Ukraine.

Asked about a quote from Kremlin spokesman Dmitry Peskov, who said earlier that Boris Johnson was the "most active participant in the race to be anti-Russian”, the UK PM insisted that he was "not remotely anti-Russian".

He said he was sympathetic to the Russian people - but not to their leader Vladimir Putin.

"We all agree that what Putin is doing is utterly catastrophic, his invasion of Ukraine is inhuman and barbaric and the conduct of that invasion is moving into the type of behaviour that we haven't seen in the continent of Europe for 80 years," he says.

Johnson says there is an "agony everyone feels in this group [Nato]" over its inability to do more to help "given the constraints we face".

The UK PM again rules out a no-fly zone over Ukraine - saying it would involve the RAF taking down Russian fast jets. No country in Nato is going to do that, he adds.

But Johnson says Nato is looking at providing missiles for Ukraine to defend itself from the air - and also from Grad rocket launchers - which he says have been merciless in their onslaught.

In addition to the doubling of lethal aid to Ukraine, Johnson says the UK must support Ukraine against its "bullying neighbour" in the long term.

"This is just the beginning," he says.

The UK has sanctioned more than 1,000 Russian individuals and entities so far in the toughest sanctions the UK has ever imposed, Johnson says.

"The message Putin can take is: Ukraine is not alone. We stand with the people of Kyiv, Mariupol, Lviv and Donetsk," he says.

"As President Zelensky himself has said, the people of Ukraine must prevail and Putin must fail - and he will."

UK Prime Minister Boris Johnson is holding a news conference following today's Nato summit and G7 meeting.

Johnson says the UK will work with like-minded allies to "ramp up lethal aid for Ukraine".

He says that Britain has promised 6,000 additional missiles and will more than double the lethal aid the UK has already provided for Ukraine.

"We must support a free and democratic Ukraine in the long term," he says.

Prime Minister Boris Johnson has begun his media briefing.

Stay with us for live updates.

Image source, EPA

German Chancellor Olaf Scholz has also been speaking following the Nato meeting - he warned Russia against any use of chemical weapons in Ukraine.

"Should Russia be preparing a false-flag operation in order to use such weapons, this would be in violation of all rules, agreements and conventions," he said.

"It is our concern not only to point this out but also to warn in the conversations we have: Don't do it," he added.

Sanctions on Russia were already having a strong impact and G7 nations were prepared to add more sanctions if necessary, he said.

However he said it had been a deliberate decision to exclude imports of Russian energy from sanctions.

Responding to a Russian announcement that Russian energy would now have to be paid for in Russia's rouble currency, Scholz said details including currency had already been fixed in contracts.

Germany would begin construction of terminals for imports of liquefied natural gas (LNG) this year, he said. The US is a major exporter of LNG.

A month on, the worst may be yet to comepublished at 16:44 Greenwich Mean Time 24 March 2022

16:44 GMT 24 March 2022

Lyse Doucet
Kyiv, BBC News

Image source, Reuters

Every life in this country has been upended by Russia’s invasion of Ukraine. It’s been a month like no other for this country and countries beyond its borders.

A month ago it was thought that Russian forces heading here from the Belarusian border would be in the capital within days. Hostomel Airport just west of Kyiv had already been attacked and captured. But now, Hostomel Airport is still contested and Russia still hasn’t seized a major city of symbolic and strategic value.

Not only are the Ukrainians holding ground, they’re also going on the offensive. They’ve retaken Makariv, west of Kyiv, and territory in the south. But Russia continues to attack. It’s now being called a “war of attrition”, with a deep sense of foreboding, that as bad as it’s been, the worst could still be to come.

We’ve been hearing all along that peace talks have been making progress, from negotiators and from mediators. But now, one month on, the talks are described as more “realistic”.

President Putin apparently doesn’t call for the removal of President Zelensky and his team, or of the Ukrainian military. And similarly, Ukraine has understood that it’s not going to join Nato any time soon, if at all. But the issues of territory – of what Russia wants to keep remain the most contentious issues of all.

Mediators say President Putin will meet President Zelensky when the time is right, but one month on, it does seem the time isn’t right yet.