Foreign secretary says he hopes for a quick resolution to the crisis but that the situation is still fraught with many dangers

William Hague, the foreign secretary, has issued a warning to Russia not to try to undermine Ukraine's economic relations with the rest of the world after the ousting of the country's president, Viktor Yanukovych.

Hague said he hoped there would be a very quick resolution after the "horrific bloodshed" seen during the week, but that it remained an unpredictable situation fraught with many dangers.

Asked on the BBC's Andrew Marr Show whether Russia could send in tanks in an effort to maintain its influence in Ukraine, Hague said it would not be in the country's interest. "We don't know, of course, what Russia's next reaction will be," he added.

"We do know that Russia, as well as the United States, has said a few days ago that they would get behind a deal that had been made, that deal has now been overtaken by events and this is the importance of us continuing a dialogue with Russia."

He said the British government had been in regular contact with the Moscow to try to resolve the crisis since David Cameron spoke to Vladimir Putin a few days ago. Now that Yanukovych has lost control of the parliament and the capital, there are fears that Russia may attempt to promote separatist movements in Crimea, which is largely ethnically Russian.

The protests in Ukraine, which have led to dozens of deaths, were partly sparked by Yanukovych's decision to back away from efforts to join the EU in favour of closer ties with Russia.

"We are talking to the Russians. This is a very important question. It's very important for us to continue to try to persuade Russia that this need not be a zero sum game," Hague said. "It's in the interest of the people of the Ukraine to be able to trade more freely with the EU, it's in the interests of the people of Russia for that to happen as well.

"The prime minister spoke to president Putin about this on Thursday. I will be talking to foreign minister Lavrov of Russia, so we are in constant discussions … if there is an economic package, it will be important that Russia doesn't do anything to undermine that economic package and is working in cooperation and support of it. So a lot of work to do with Russia over the coming days."

Yanukovych fled the capital on Saturday as the country's parliament voted to strip him of his powers. He has likened the actions of his opponents to those of the Nazis and said he would battle to stay in power. Ukraine's former prime minister Yulia Tymoshenko was released from detention and pledged to stand in elections later this year.

Hague said the next urgent step was for the country to form an inclusive government of national unity and agree constitutional arrangements for elections in May.

"There is an opportunity, but there are still many dangers of course,"

he said. "The political situation, even among the opposition is very complex. It's clearly been a very divided country."

Speaking in Sydney after the G20 finance ministers conference, George Osborne, the chancellor, said British cash is available to help Ukraine return to stability.

"We are here ready to help just as soon as there is someone at the end of the telephone. We should be there with a chequebook to help the people of Ukraine rebuild their country," he said.