More on the dramatic last-minute appeal by Ukraine's president to Russian citizens.

Referring to the Russian soldiers deployed along Ukraine's borders, Zelensky said the leadership in Moscow had approved "their step forward".

"To the territory of another country. And this step could be the beginning of a big war on the European continent," he added.

Zelensky also dismissed suggestions by Russian officials that he would give an order to start an offensive in Ukraine's eastern Donbas region.

Ukraine's President Zelenksy also says that Russia has massed "nearly 200,000 troops on Ukraine's borders and thousands of combat vehicles".

In a late-night televised speech, Zelensky switched into Russian to "address Russian citizens as a citizen of Ukraine".

"Hear us. The Ukrainian people want peace. The Ukrainian authorities want peace," he said.

Image source, EPA

Ukraine President Volodymyr Zelensky has just said that Russia has approved an offensive against Ukraine.

He also said President Vladimir Putin had not replied to his invitation to hold talks.

Roman Yaremchuk, a Ukrainian striker for Portugal's Benfica, has staged a patriotic goal celebration, after rescuing a point in a Champions League game against Amsterdam's Ajax on Wednesday night.

Yaremchuk equalised late in the game, making it 2-2 in the first leg of the tie played in Lisbon.

He took off his club jersey, proudly revealing the Ukrainian trident - the nation's coat of arms - on a shirt underneath.

Image source, Getty Images

It's not the first time Ukraine's elite athletes have shown their support for the country, amid tensions with Russia.

On Tuesday, Oleksandr Zinchenko, a defender at England's Manchester City, wrote in an Instagram post (in Ukrainian): "We will not give up what is ours! Glory to Ukraine."

Ukrainian Foreign Minister Dmytro Kuleba says he has demanded an urgent meeting of the UN Security Council about the reported appeal of pro-Russian separatists to Moscow for military assistance.

The Kremlin says the separatist leaders of Donetsk and Luhansk have asked Russian forces to enter their breakaway regions in eastern Ukraine to "help repel the aggression by the armed forces and units of Ukraine".

Earlier Kuleba tweeted that Russia had evacuated night-shift staff at a major chemical plant in Crimea.

He said the evacuation of the plant was a possible preparation for a staged provocation by Russia.

"Moscow seems to have no limits in attempts to falsify pretexts for further aggression," he wrote.

Image source, Getty Images

Australian Prime Minister Scott Morrison says their "first tranche" of sanctions will take effect from the end of March.

They will target specific Russian individuals and corporations "who are at the heart of this bullying and aggressive behaviour".

"The reason we're doing this is there must be a price for the unprovoked, unlawful, unwarranted, unjustified attacks and threats and intimidation that has been imposed by Russia on Ukraine," Morrison tells reporters in Sydney on Thursday.

Ukrainians currently in Australia and with visas that expire by 30 June will have them extended by six months.

Morrison says Australia is co-ordinating its response with allies, particularly the US and UK.

The request for security assistance that the Kremlin says came from the leaders of Donetsk and Luhansk, two eastern Ukrainian breakaway regions, clears the way for large numbers of Russian soldiers to move into the territory.

The letters from the two leaders of Donetsk and Luhansk were dated 22 February, according to Russian media.

The appeals come after Russian President Vladimir Putin on Monday recognised the independence of the two "republics" and signed defence treaties with them.

Some parts of the regions - which only Russia has recognised as independent nations - are still held by Ukrainian forces, spurring concerns that Russia may try to remove them from the area by force.

Around 150,000 Russian troops are amassed along Ukraine's border. Earlier on Wednesday, the US said Russian troops have continued flowing into the rebel-held regions.

Only on Tuesday, Russia's parliament gave the government permission to use military force abroad.

The announcement from the Kremlin tonight comes as Ukraine declares a 30-day state of emergency, and orders all military reservists not to leave the country.

Pro-Ukrainian demonstrations have been held outside Russian embassies in Europe.

This protest in Copenhagen, Denmark, was organised by youth organisations on Facebook.

Image source, EPA

Some pro-Ukrainian protesters also gathered outside Russia's embassy in London

Image source, Reuters

One placard read "block Russian wallets". A raft of Western sanctions have been imposed on Moscow over the last few days.

Image source, Reuters

Paul Adams
BBC diplomatic correspondent

Image source, Getty Images

According to Russian media, the leaders in Donetsk and Luhansk - the two self-declared “people’s republics” in eastern Ukraine - have written to Vladimir Putin, asking for help in repelling what they describe as aggression by Ukraine’s military.

Both have accused Ukraine of attacking schools and hospitals and of being unwilling to end the war in the Donbas.

All the evidence in recent days points to the Russian-backed separatists being the ones responsible for the latest escalation, not Ukraine.

Tonight’s appeal to the Kremlin appears to be the latest in a series of pre-planned moves which are pushing this country closer to a wider conflict.

On Monday, Mr Putin offered to send in what he called “peacekeepers” to defend the two separatist areas – which he had just recognised as independent.

So far, there has been little or no sign of additional Russian troops crossing the border. That could now change.

This is another moment of extreme danger for Ukraine.

Image source, Reuters

The Russian-backed separatist leader of a Ukrainian breakaway region has said that Ukrainian forces should withdraw from the territory and take their weapons with them.

Denis Pushilin, head of the Donetsk People's Republic, told Russian state media that the departure of Ukrainian troops was the best option.

Russia has recognised two breakaway Ukrainian regions, including Pushilin's, as independent states.

The separatists lay claim to a far larger area of territory in Ukraine than they currently control.

Image source, Reuters

The Nord Stream 2 pipeline that connects Russia and Germany is "currently dead at the bottom of the sea", White House press secretary Jen Psaki said.

"It's not happening, it's not moving forward, it hasn't been operational for some time," she told the daily press briefing.

The White House on Wednesday announced sanctions on the makers of the Nord Stream 2 pipeline that connects Russia and Germany.

The €10bn (£8.4bn) project was completed last September.

The US decision comes after German Chancellor Olaf Scholz announced the pipeline would stay closed in response to Russia's moves against Ukraine.

President Putin has had to adapt his strategy because of intelligence released by the US, the White House press secretary has said.

"President Putin did not expect the United States to have the level of information that we have, did not expect us to put out this amount of information that we have put out, did not expect the global community to be as unified, including in how unified the global community was in putting out the sanctions," Jen Psaki said.

"Our assessment is that he is improvising, adapting and having to respond and adapt his own actions, as we are responding to him."

White House press secretary Jen Psaki reiterates the US will not be going to war with Russia, even if it wages a full-scale invasion of Ukraine.

"We are not going to be in a war with Russia or putting military troops on the ground in Ukraine fighting Russia," she said.

A reporter asked whether that stands even if Russia "takes all of Ukraine".

"That is several steps down the road, but what I will tell you is that the president has been crystal clear and consistent - he is not sending US troops to Ukraine."

Image source, Getty Images

US Department of State spokesman Ned Price has called negotiations with Russia "diplomatic kabuki theatre" - referring to the Japanese dance-drama.

Russia is "making statements that they are committed to a diplomatic path while their actions suggest exactly the opposite", he said at a briefing in Washington.

"That is not an environment in which diplomacy can achieve the results that it needs to achieve."

He reiterated that the US was prepared to continue negotiations, but only if Russia was serious about avoiding war.

Price also called the newly announced US sanctions on Nord Steam 2 "the beginning of our response".

"If Putin escalates further, we will escalate further using additional sanctions and export controls, which we've yet to unveil, but are fully prepared to implement."

He added: "The invasion remains potentially imminent."

Image source, Getty Images

Putin spokesman Dmitry Peskov's new statement, in which he says that the breakaway provinces of Donetsk and Luhansk are asking for protection from Russian forces, goes on to accuse Ukraine of fomenting hostilities.

"As the aggression by the Ukrainian armed forces continues, civilian and industrial infrastructure, schools, hospitals, kindergartens are being destroyed in the republics," he said, referring to the two regions of eastern Ukraine that Russia has now recognised as independent nations.

"Actions by the Kyiv regime show that it is unwilling to end the war in Donbas," he says, adding: "Kyiv continues to increase its military presence on the contact line, receiving comprehensive support, including military support, from the US and other Western countries."

He added that Russian troops are operating with the "purpose of preventing victims among peaceful residents and a humanitarian catastrophe".

President Putin has accused Ukraine of supporting a "genocide" in the Donbas region.

There is no evidence of genocide in eastern Ukraine, though more than 14,000 people have been killed since 2014 in an ongoing conflict between Ukraine and Russian-backed rebels.

Image source, Getty Images

Kremlin spokesman Dmitry Peskov has said the separatist leaders of Donetsk and Luhansk have asked Russian forces to enter their breakaway regions in eastern Ukraine to "help repel the aggression by the armed forces and units of Ukraine".

"Their appeals stress that because of the deteriorating situation and Kyiv's threats, citizens of the republics have been forced to leave their homes and their evacuation to Russia continues," he said, according to TASS news agency.

"The Kyiv regime is geared towards resolving the conflict by force," states an appeal by the separatists, relayed by Peskov.

Russian authorities have cited a number of incidents in eastern Ukraine as a possible justification for military action.

But the US has accused Russia of plotting so-called false flag incidents, provocations staged to create a pretext for action.

Russian troops could attack Ukraine at any time, White House Press Secretary Jen Psaki has just told reporters at her daily briefing.

"I'm not going to give an additional timeline to it. We have been saying it could happen at any time and they are in an attack position for some time now," she said.

Psaki was responding to a question about Australian Prime Minister Scott Morrison's statement on Wednesday that an invasion of Ukraine was “likely to occur within the next 24 hours”.

Personal sanctions against President Putin are "an option on the table", White House press secretary Jen Psaki just said.

"Sanctions are designed to be increased and escalatory," she said.

Let's remind ourselves of the most recently announced sanctions by Western countries against Russia:

On Wednesday the European Union approved new measures targeting specific Russians with travel bans and asset freezes, and restricting the Russian state's access to EU financial markets. The bloc's trade chief told Reuters that export restrictions would follow if Russia invades Ukraine further.

In Washington, President Biden on Tuesday announced a "first tranche" of wide-ranging sanctions from the United States. The moves target Moscow's foreign debt, preventing the Russian state from accessing financing through Western financial institutions. Restrictions have also been placed on five members of Putin's inner-circle and two state-owned Russian banks.

Also on Tuesday, the UK announced sanctions targeting three Russian billionaires and five banks. On Wednesday afternoon Prime Minister Boris Johnson defended the measures as putting the UK "out in front", but some MPs criticised them for not going far enough.

Image source, Reuters

John Kirby, spokesman for the Department of Defense, says the US believes more Russian troops are entering the Donbas region of eastern Ukraine.

"We certainly believe that additional Russian forces are moving into that region, not beyond that region, that we have seen," he said at the Pentagon.

"But we can't confirm with any great specificity the numbers, and what the formations are, and what the capabilities are," he continued.

"But we certainly believe that that's happening."

Mr Kirby added that Russian troops continue to amass at the border, and are prepared to push into Ukraine should Vladimir Putin order a full-scale invasion.

"We believe they are ready. I'll just leave it at that. They are ready," he warned.

Albiy Shudrya
BBC Ukrainian Service

First thing you see when approaching Avdiivka are the clouds of smoke hanging over the city's chemical plant. It's a bizarre sensation to hear the shooting in the distance punctuate the silence.

The head of the local government here is Vitaliy Barabash, who does his job wearing military fatigues.

I find him in his office, flanked by Ukrainian flags and a rocket-propelled grenade launcher. He's busy negotiating on the phone to restore water supply to the city.

In 2014 Russia-backed separatists took control of this city for almost three months.

Barabash says that many mistakes were made and blames aggressive Russian propaganda that allowed groups of separatists to capture local administrations of many cities in Donbas.

"Ukrainian servicemen were not ready to shoot at Russian troops. That’s how we were raised, Russians were considered as a brotherly nation; we were brothers," he says.

Vladimir Putin, he says, "has just gone mad".

"Frankly, I can’t say he’s stupid. As a person he's quite clever. He always has several options and thinks through each of them. But for the last eight years he falls asleep and gets up with only one thought in his head: 'What mean thing can I do for my Ukrainian neighbour?'"

He says Ukrainians in his town will react differently than in 2014.

"The main thing is that now our troops have no fear to shoot. And, secondly, we have clear understanding of who is our enemy."