Ukraine could face imminent economic collapse without support from the international community, foreign secretary William Hague has warned.
Mr Hague told MPs he would be raising the country's financial plight in the wake of the ousting of President Viktor Yanukovych with the International Monetary Fund when he visits Washington this week.
"Ukraine's financial situation is very serious and without outside assistance may not be sustainable. An economic crisis in Ukraine would be a grave threat to the country's stability and have damaging wider consequences," he said in a Commons statement.
The foreign secretary, who leaves for the United States tonight, said the IMF was the organisation best placed to provide the financial support and technical advice the country needed.
While support could be provided quickly once it was requested by a new government in Kiev, Mr Hague said it would require a commitment to reform.
"It requires a stable and legitimate government to be in place and a commitment to the reforms necessary to produce economic stability. International financial support cannot be provided without conditions and clarity that it will be put to proper use," he said.
Mr Hague, who discussed the issue by telephone with Russian foreign minister Sergey Lavrov, said it was not clear whether a Russian bailout package offered by Moscow to entice Mr Yanukovych not to sign an association agreement with the European Union would now go ahead.
While the EU offer remained "on the table", he said it was vital that it did not become a "binary choice" for the Ukraine between co-operation with Russia or co-operation with Europe.
"This is not about a choice for Ukraine between Russia and the EU. It is about setting the country on a democratic path for the future. We want the people of Ukraine to be free to determine their own future," he said.
"It is important that all channels of communication between the EU and Russia stay open."
Despite tensions between western Ukraine, where opposition to Mr Yanukovych was strongest, and the Russian-speaking east, which traditionally looks more to Moscow, Mr Hague said Mr Lavrov had emphasised Russia's commitment to the territorial integrity of Ukraine.
He told MPs that the Russian foreign minister had not raised any prospect of military intervention by the Kremlin in the country.
"Any notion of this kind is manifestly not in the interests of Russia, as well as not in the interests of Ukraine. I hope that point is well understood," he said.
He stressed that the EU offer of association with Ukraine had not been intended as a "hostile" move towards Russia.
"We believe that closer economic links with the EU can be beneficial to the entire region, including to Russia. We are not presenting it as a strategic competition between East and West. I think it would be a mistake to do so," he said.
Volodymyr Khandogiy, Ukraine's ambassador to the UK, told Channel 4 News: "I totally cannot accept what's happening. I disagree with what happened... the use of force.
"The killing is appalling, it's unacceptable in any civilised society.
"I haven't seen, neither written nor did I hear, any oral commands but, of course, I can assume safely that what was happening on the streets of Ukraine could not have happened without the blessing of the presidency."
He added: "I apologise to my own people, that's all I can do."