The Kremlin says Russia remains open to all diplomatic contact over Ukraine and that Kyiv cutting ties with Moscow would worsen the situation.

It comes after Ukrainian President Volodymyr Zelensky said he was considering a request from his foreign ministry to break off diplomatic relations with Russia.

Kremlin spokesman Dmitry Peskov also tells reporters he is unable to say if Russian forces have already entered the two rebel-held regions in eastern Ukraine.

He says a decision to send in forces would depend on how the situation developed.

The certification of the Nord Stream 2 gas pipeline cannot go ahead given Russia's latest actions, German Chancellor Olaf Scholz says.

The pipeline between Russia and Germany was completed last September but is not yet operating.

You can read more about the pipeline and how it fits into the crisis here.

More now from Ukrainian President Volodymyr Zelensky.

Speaking a news conference in Kyiv, he tells reporters that Moscow's recognition of separatist regimes in eastern Ukraine represents a threat to the security of other European nations, as well as his own.

"The security of the borders of one country decide the security of another country's," he says.

"We are not a member of the European Union, or of Nato - but if we have a full-scale escalation, a full-scale invasion by the Russian Federation, our neighbours would be put at risk... Moldova, Lithuania, Lithuania, Latvia, Estonia."

"God forbid I do not want it, no one wants war. In Ukraine, people only want peace. But we must prepare for any steps of aggression."

We've heard more from Ukraine's president, he says he is considering a request from his foreign ministry to break off diplomatic relations with Russia.

Speaking at a news conference alongside his Estonian counterpart, Volodymyr Zelensky urges his European allies not to wait to impose sanctions against Moscow.

He plays down the prospect of a large-scale conflict with Russia but says he is prepared to introduce martial law if it happens.

Ukraine's president has demanded an immediate halt to the Nord Stream 2 gas pipeline from Russia to Germany.

The pipeline was completed last September, but is not yet operating.

Volodymyr Zelensky tells a press conference, Russia must be punished for its recognition of two rebel-held regions in eastern Ukraine with "immediate sanctions", including "the complete stop of Nord Stream 2".

Marc Weller
Professor of international law, University of Cambridge

Image source, Getty Images

For a quarter of a century, Russia has already strained international law and used force. So its use of force against Ukraine in 2014, and its deployment of “peacekeepers” in the east now is not really a “new normal”.

Back in 1999, the Kremlin disowned its peace agreement with Russia's southern republic of Chechnya, destroying the territory, much as it has now torn up the internatinal Minsk accords that were meant to keep the peace in eastern Ukraine.

It has illegally kept forces in neighbouring states like Georgia, Moldova and Ukraine, creating pseudo-states beyond the control of the central governments.

In 2008 it forcibly detached South Ossetia and Abkhazia from Georgia, falsely claiming to rescue local populations. Its deployment of “little green men” brought Crimea to declare itself independent and become annexed by Russia in 2014.

The West has hidden behind ineffectual mediation attempts, refusing to name these acts of aggression when they occurred. Putin was emboldened to use force even more openly. Recognising Luhansk and Donetsk as states is a similar ploy to cover the invasion of Ukraine, which has now already occurred.

Image source, Getty Images

Ukraine's defence minister has accused Russian leader Vladimir Putin of trying to revive the former Union of Soviet Socialist Republics (USSR).

In a letter addressed to Kyiv's armed forces, Oleksii Reznikov said Moscow's decision to recognise two breakaway regions in eastern Ukraine shows that the Kremlin has taken another step towards the revival of the bloc, which collapsed in 1991.

"The Kremlin took another step towards the revival of the Soviet Union. With the new Warsaw Pact and the new Berlin Wall," Reznikov wrote. "The only thing that separates from this is Ukraine and the Ukrainian army."

"Our choice is very simple - to defend our country, our home, our relatives. Nothing has changed for us," he went on.

"There are some tough challenges ahead. There will be a loss. You will have to go through the pain, overcome fear and betrayal. But victory awaits us. Because we are on our land and the truth is behind us."

Reznikov also accused Moscow of "criminal" behaviour and of attempting to "hold the free world hostage".

Ukraine's ambassador to the UK has said that he is extremely concerned about Russian leader Vladimir Putin's plans for his country.

Speaking last night to the BBC's Newsnight programme, Vadym Prystaiko said Putin's description of Ukraine as "a historical mistake that has to be fixed" was alarming.

"You have to be worried about what he has in mind," Prystaiko said.

Putin was accused of writing his own version of history during an hour-long speech on Monday night in which he made a litany of false accusations against Ukraine and questioned its status as a country.

Image source, PA Media

It is clear Russia has broken international law, UK Defence Secretary Ben Wallace says.

Opening a meeting of the UK-led Joint Expeditionary Force - made up of defence ministers from the Baltic states and Nordic countries - he notes President Putin's recognition of two rebel-held regions in eastern Ukraine is "a very worrying sign".

"And we've seen in open source reporting... Russian military equipment is moving into that region now," he says, adding that this is awaiting verification.

"It's incredibly serious what's happening in Ukraine," he says. "This is a sovereign state that has now had some of its land effectively annexed from it. This is a sovereign state that is a democratic state in Europe, all of us in Europe should worry.

"And we should not hesitate to take whatever action we need to to deter President Putin from undermining both Nato but also Europe, and more importantly, our values."

Image source, Reuters

Oil prices are climbing over fears that the Ukraine-Russia crisis will disrupt supply chains across the world.

Futures of Brent crude, the international benchmark, reached a seven-year high of almost $98 (£72) on Tuesday after Russia recognised breakaway rebel regions in Ukraine's east as independent states.

The UK and several western allies have threatened sanctions on the country.

Russia is the second largest exporter of crude oil after Saudi Arabia. It is also the world's top producer of natural gas.

Sanctions forcing Russia to supply less crude or natural gas would have "important impact on the global economy," says Sue Trinh of Manulife Investment Management.

The former UK ambassador to Russia says a diplomatic solution to the Ukraine crisis will be impossible as long as Vladimir Putin remains in power.

Sir Andrew Wood told the BBC, Putin cannot "recognise what a diplomatic solution would be" and noted "his word is obviously worth nothing".

"A diplomatic solution for him would be not just us saying that we aren't going to invite Ukraine into Nato, it would be accepting his total control of that country," Sir Andrew said.

Addressing the question of sanctions, Sir Andrew called for a full package of measures to be imposed against Moscow immediately.

He urged western leaders to target Russian banks and to bring an immediate end to plans to make the Nord Stream 2 gas pipeline operational.

He added that the recognition of separatist regions marked a dangerous moment for Putin, noting that "the people of Russia do not want war" and said that "they are not as enchanted with Putin as they once were".

Sarah Rainsford
BBC Eastern Europe Correspondent

Russian president Vladimir Putin's late-night televised speech from the Kremlin was laced with anger, historical grievances and challenges to the West.

This speech was Putin the angry; impatient and directly threatening. It felt like Russia's president was getting 20-odd years of hurt off his chest and hitting back.

"You didn't want us to be friends," was how he put it to the West, "but you didn't have to make an enemy of us".

There was a lot we've heard before, repackaged for this moment when he knows he has maximum attention.

With this speech, Putin was clearly ceding no ground on his key security demands: Nato expansion must be rolled back, and Ukrainian membership is a red line. He complained that Russia's concerns had been ignored as irrelevant for years and accused the West of trying to "contain" Russia as a resurgent global force.

Mr Putin's focus on Ukraine felt obsessive, like a man who thinks about little else. At times it sounded like a bid to run for president there, it was so detailed.

And, of course, there was his re-writing of Ukrainian history, to claim it has never really been a state. In today's context, that had deeply ominous overtones.

Recognising the two breakaway regions of Ukraine could mean Russian troops go in openly, very soon - invited as "peacemakers".

The two regions are home to Russian-backed rebels who have been fighting Ukrainian forces since 2014.

Or there could be a pause, as the Russia leader waits to see his opponent's next move.

In all this, Ukraine is the battleground. But it's also a game of brinkmanship between Russia and the West, rapidly building to a showdown.

Boris Johnson says shifting away from Russian oil and gas would help with the UK's energy security.

He says the volatility in gas prices in Europe is a "consequence of that failure" to stand up to Russia in 2014 when Crimea was annexed.

The PM says: "In the UK we have been able to reduce our dependency on Russian gas very substantially. Only 3% of our gas supplies now come from Russia."

Johnson says the response includes granting licences for UK gas reserves but also shifting to low-carbon energy, including nuclear power.

He added: "The faster this country can be more self-reliant on our own energy, the more prosperous we will be, but also, of course, the more sustainable our energy prices will be, and that will benefit the UK consumer."

Boris Johnson says the UK's sanctions will hit the "economic interests that have been supporting Russia's war machine".

"They will hit Russia very hard and there is a lot more that we are going to do in the event of an invasion," he says.

"Be in no doubt that if Russian companies are prevented from raising capital on the UK financial markets, if we unpeel the facade of Russian ownership of companies, of property, it will start to hurt."

Boris Johnson is speaking now following the emergency Cobra meeting - the UK government committee that handles emergencies.

The prime minister says Russian President Vladimir Putin has now violated Ukrainian sovereignty by sending troops in and "completely torn up" international law.

"We will immediately institute a package of international sanctions," he says.

"This is just the first of a barrage of sanctions because we believe there will be more Russian irrational behaviour to come," he says.

Paul Adams
BBC diplomatic correspondent

In one sense, Russia’s action last night changes nothing.

Russian troops have been in and out of the Donbas since 2014. I met “volunteers” manning checkpoints after the capture of Debaltseve in February 2015.

For eight years, Moscow has organised, equipped and funded the separatists of the “People’s Republics” of Donetsk and Luhansk.

So the arrival of so-called “peacekeepers” will merely represent the latest, and most official, stage of Russia’s occupation.

Western leaders will now need to decide whether this represents the “further invasion” they’ve been warning against.

But with such a vast war machine in place around Ukraine’s borders, it’s very hard to see why Vladimir Putin would stop now.

Huge numbers of Russian troops are now “tactically deployed” within a short striking distance of Ukraine’s borders.

Western officials believe they can only be there to mount an invasion and continue to insist that this could come at any moment.

As always in the crisis, we come back to a fundamental question: what does Vladimir Putin really want?

We are getting some news from the UK government's emergency Cobra meeting on Ukraine.

Prime Minister Boris Johnson has said the "first barrage of UK economic sanctions against Russia" will be revealed today as he warned Vladimir Putin is bent on a "full-scale invasion of Ukraine".

But Putin is going to find he has "gravely miscalculated", Johnson says.

Johnson is expected to give a statement to Parliament at 12:30 GMT and we will bring you live updates.

Image source, Getty Images

EU foreign ministers will adopt sanctions on Tuesday afternoon against Russia over its recognition and incursion into Ukrainian separatist regions, the bloc's foreign policy chief Josep Borrell has said.

The 74-year-old told reporters while he wouldn't call Moscow's deployment of troops to separatist regions "a fully-fledged invasion", he emphasised that the EU considers the region as Kyiv's territory and said that "Russian troops are on Ukrainian soil".

Speaking ahead of a ministerial forum in Paris, Borrell said "our response will be in the form of sanctions, whose extent the ministers will decide" and noted that he expected members states to come to "a unanimous decision"

Envoys from members states will meet on Tuesday morning where EU officials expect there to be some debate on the strength of measures to be applied, with some countries favouring a more limited response.

We are reporting the fallout after Russian President Vladimir Putin recognised breakaway rebel regions in Ukraine's east as independent states - but where are they?

The self-declared people's republics of Donetsk and Luhansk are on eastern Ukraine's border with Russia.

Both regions are home to Russia-backed rebels who have been fighting Ukrainian forces since 2014.

Putin says he will send Russian troops in to perform so-called "peacekeeping functions" - but Western powers believe he is paving the way for a new invasion of Ukraine that could go well beyond the self-declared republics. For a start, a large part of the Donetsk and Luhansk areas is still controlled by Ukraine.

The UK is among a number of countries to announce sanctions on Russia and government sources say these punishments would be "ratcheted up" if Russian invaded Ukraine.

BBC Breakfast wraps up Sajid Javid's interview by asking if Russian President Vladimir Putin's speech last night means we are "nowhere near a diplomtic solution".

The UK health secretary replies: "It does seem that way which is obviously something that no one wanted to see."

He says there have been "huge efforts" by the UK and its allies to try and to have dialogue with Russia. These have included recent visits to Russia by the UK's foreign and defence secretaries and talks between UK Prime Minister Boris Johnson and Russian President Vladimir Putin, he says.

"But clearly President Putin has chosen a different route and we cannot allow this to stand," he says.

Javid says the PM is in a Cobra meeting discussing what action the UK will take and he will set out his plans in parliament later today.