A top general has warned Ukraine will be"flooded" with Russian blood if Vladimir Putin orders an invasion.
Oleksandr Syrskyi, the Commander of the Ground Forces of Ukraine, issued the threat as the Kremlin continues to amass forces at the country's border.
General Syrskyi's chilling promise echoed the chants of protesters who gathered in Kyiv today and swore to fight foreign aggression with their "last breath and bullet".
A German newspaper previously claimed US spies received details about Russia's invasion plan, which reportedly sets the date of invasion as February 16.
The general, who is currently conducting military drills with troops, has warned an invasion will not be a "simple walk in the park".
“The armed forces of Ukraine are ready,” the 56-year-old told Sky News.
“We are capable and we will not give up a single metre of Ukrainian land without a fight.
"We are ready, and we warn them 'it won't be a simple walk in the park. Each metre of that land will be flooded with the occupants' blood’.
"I trust in the Ukrainian service members. I trust in our armed forces and I trust in our victory."
US President Joe Biden today warned his Russian counterpart Vladimir Putin that invading Ukraine would cause "widespread human suffering".
The White House account of the crisis call on Saturday said Mr Biden warned an attack would "diminish Russia's standing" as the West pinned hopes on diplomacy to avert war.
They were said to have spoken for around an hour after French President Emmanuel Macron also shared a call with Mr Putin, with fears of an imminent attack heightening.
British, American and German citizens have been told to leave Ukraine immediately as more than 100,000 Russian troops mass on the border.
Fears are growing that flights out of the country may become difficult if the Russians start a deadly "aerial bombardment of Kyiv".
The US has also ordered non-emergency embassy staff to leave Ukraine, following previous withdrawals of diplomats by America and Britain.
The plans were passed to President Joe Biden's Government and have been discussed by NATO allies, according to Der Spiegel.
Mr Biden's national security adviser Jake Sullivan said an attack before the end of the Winter Olympics on February 20 was a "credible prospect", assigning it a "very, very distinct possibility".
He warned a Russian attack on Ukraine could begin any day and would likely start with an air assault.
Mr Sullivan said new Russian forces were arriving at the border and are in a position to "mount a major military operation in Ukraine any day now", which could include a "rapid assault on the city of Kyiv" or on other parts of the country.
Speaking from the White House, he said Russia could choose "in very short order to commence a major military action against Ukraine", but stressed the US does not know whether Mr Putin has made a final decision.
Mr Sullivan said the "threat is now immediate enough" to urge Americans to leave Ukraine "as soon as possible and in any event in the next 24 to 48 hours".
It comes as the US State Department ordered non-emergency embassy staff to leave Ukraine on Saturday.
The State Department tweeted: "Despite the reduction in diplomatic staff, the core embassy team, our dedicated Ukrainian colleagues, and @StateDept and US personnel around the world will continue relentless diplomatic and assistance efforts in support of Ukraine's security, democracy, and prosperity."
Meanwhile, UK armed forces minister James Heappey said British troops helping with training in Ukraine will be leaving the country this weekend - and there will be no UK soldiers in Ukraine if Russia does invade.
Having sent UK personnel to train Ukrainians on the anti-tank missiles supplied by Britain, Mr Heappey said: "All of them will be withdrawn. There will be no British troops in Ukraine if there is to be a conflict there."
He added to BBC Radio 4's Today programme: "They will be leaving over the course of the weekend."
The minister previously warned Brits in Ukraine not to expect a military evacuation if Russia invades.
"British nationals should leave Ukraine immediately by any means possible and they should not expect, as they saw in the summer with Afghanistan, that there would be any possibility of a military evacuation," he said.
