Tensions between Ukraine and Russia, which has massed troops along the border, has drawn Washington and Moscow into a Cold War-style stand-off.
Here is a timeline of the spiralling situation.
On November 10, NATO warns Moscow about taking “aggressive action” after Washington reports unusual troops movements near the Ukrainian border.
It comes five months after Ukraine accused its larger neighbour of massing soldiers along its eastern frontier and in Crimea, which Russia annexed in 2014.
Violence in the country’s east, grabbed by Russia-backed separatists after the invasion, also surges.
Russian President Vladimir Putin accuses the West of “supplying modern weapons to Kyiv” and staging provocative military exercises.
On November 28, Ukraine says Russia is massing nearly 92,000 troops for an offensive at the end of January or early February.
Moscow denies this outright and three days later accuses Kyiv of a military build-up of its own, demanding “legal guarantees” that it will never join NATO.
On December 7, US President Joe Biden threatens Putin with “strong economic and other measures” if he invades Ukraine but rules out sending troops to support Kyiv.
Putin again demands a stop to NATO’s eastward expansion.
On December 16, the EU and NATO warn of “massive strategic consequences if there was a further attack on Ukraine’s territorial integrity”.
The next day Moscow puts forward proposals to limit US influence on former Soviet states.
Talks to ease tensions
On December 28, Washington and Moscow announce European security talks and two days later Biden warns Putin that progress depends on “de-escalation” of the Ukraine stand-off.
On January 2, 2022 Biden assures Ukraine that Washington and its allies would “respond decisively” if Russia moves to invade.
Three days later EU foreign policy chief Josep Borrell visits the frontline in the east as he pledges the bloc’s full support for Ukraine.
On January 8, a senior White House official says the US is ready to discuss with Russia the two countries’ missile systems and military exercises.
Week of diplomacy
On January 10, top US and Russian officials begin a week of tense talks in Geneva.
Two days later, NATO and Russia lay out stark differences on Ukraine at a meeting of the NATO-Russia council.
A cyberattack on January 14 briefly knocks out key government websites in Ukraine.
Kyiv says it has uncovered clues Russia could have been behind it.
The same day US officials allege Russia has operatives in place to carry out a “false flag” operation to create a pretext to invade Ukraine. The Kremlin denies this.
Build-up in Belarus
On Monday Russian troops begin arriving in Belarus for snap military drills, which Moscow says are aimed at “thwarting external aggression”.
US officials say the size of the force is “beyond what we’d expect of a normal exercise”.
The next day Washington warns that “Russia could at any point launch an attack on Ukraine.”
Meanwhile Moscow says it wants a response from the West to its demands before any more talks on the eve of Blinken visiting Ukraine.
On Wednesday Washington announces an extra $200 million in security aid to Kyiv.
Biden fears ‘invasion’
Washington gives the green light to Baltic nations to rush US-made weapons to Ukraine Thursday.
It also hits four prominent Ukrainians with sanctions saying they are “pawns” of Russian intelligence working to destabilise the country.
Biden says that any incursion of Russian troops is “an invasion” after appearing to suggest a “minor” attack on Ukraine could invite a lesser response.
US Secretary of State Antony Blinken says he asked Russsian counterpart Sergei Lavrov at a meeting to prove Russia is not planning to invade Ukraine and to pull back its troops.
Washington promises a written response to Russian security demands next week.
Ukraine blames Russia for a campaign of fake bomb threats targeting society.
Baltic states move in
Ex-soviet NATO members Estonia, Latvia and Lithuania say they will send anti-tank and anti-aircraft missiles to allow Ukraine to defend itself.
Russia vows “the most serious consequences” if Washington keeps ignoring what it said were its legitimate security concerns over Ukraine.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)