Boris Johnson warns Europe is facing its 'most dangerous moment' in decades as Ukraine-Russia tensions escalate

• Boris Johnson said the Ukraine-Russia crisis was 'the most dangerous moment' Europe had faced for decades.
• The UK placed on standby 1,000 troops to go to eastern Europe in a show of solidarity against Russian aggression.

Boris Johnson warned that Europe was facing "the most dangerous moment in what is the biggest security crisis" the continent has faced in decades, warning that the prospects of avoiding a conflict appeared "grim."

Russia has amassed more than 100,000 troops on the Ukrainian border. French President Emmanuel Macron held talks with Putin in Moscow this week where he said Putin promised there would be "no deterioration or escalation" in Ukraine.

But on Thursday Russia started running 10 days of joint military drills with Belarus, a country which shares a long border with Ukraine, in a move which the US described as "escalatory."

Johnson said he believed Putin had not decided whether to launch a new incursion into Ukraine but warned that the situation could escalate dramatically in the near future.

"I don't think a decision has yet been taken but that doesn't mean that it is impossible that something absolutely disastrous could happen very soon indeed," he said at a joint press conference with NATO Secretary-General Jens Stoltenberg in Brussels on Thursday.

"Our intelligence I'm afraid to say remains grim and we're seeing the amassing of huge number of tactical battalion troops. This is the most dangerous moment in the biggest security crisis Europe has faced in decades."

The UK is placing 1,000 troops on standby to go to eastern Europe to provide support in the event of a refugee crisis in the event that Russia launches a new large-scale invasion of Ukraine.

Defence Secretary Ben Wallace, who will meet his counterpart in Moscow on Friday — said the move would show Russian President Vladimir Putin that NATO countries including the UK are consistent in their opposition to Russian aggression.

"What this is really about is saying to President Putin [that] NATO is not flaky. NATO will stand by its members, big or small," he told BBC Radio 4's Today programme.

Ukraine is not a NATO member, but Wallace said an invasion of the country would affect its NATO neighbours including Poland by prompting a refugee crisis.

Troops placed on standby would end up "wherever there were consequences from any Russian invasion into Ukraine that were going to be felt particularly badly or would risk undermining stability," he added.

"It's important to send a message to Russia to say, look, we want a dialogue, we want a way through this, but ... currently Russia is now deploying over half its combat troops ... on the borders of Ukraine and in Belarus."

"We are not just going to let that happen without NATO having a response to defend its own members."

Foreign Secretary Liz Truss arrived in Moscow on Wednesday ahead of scheduled talks on Thursday with her Russian counterpart Sergey Lavrov.

She said she planned to "make clear that Russia must immediately withdraw its forces and respect Ukraine's sovereignty or face severe consequences."

"Any incursion would be a huge mistake. Diplomacy is the only way forward and Russia must pursue that path," she said.