Thousands of Ukrainian students have joined protests in the centre of Kiev against the government's abrupt move to freeze integration with the West and tilt toward Moscow.
Kiev announced last week that it was halting preparations for the signing of a political and trade agreement with the European Union, after Russia imposed trade restrictions and threatened more to come.
Up to 3,000 students from Kiev universities walked out of lecture halls to join several thousand other protesters on two central squares, calling on president Viktor Yanukovych to change his mind and sign the agreement with the EU at a summit on Friday.
As Kiev intensified talks with Brussels in recent months, Russia restricted imports of Ukrainian steel, chocolates and other products, which Ukrainian Prime Minister Mykola Azarov said reduced this year's exports by billions. However he described Ukrainian-Russian relations as "absolutely normal," and instead blamed Kiev's turnaround on Brussels, saying it refused to provide financial aid to the struggling Ukrainian economy.
"Let us say this straight away: The European Union provided no help for us here, other than general declarations," he said. "We received no concrete help."
Mr Azarov called for trilateral talks with Russia, Ukraine and the EU and said the issue of Ukraine's integration with the bloc can be taken up again at a summit next spring, but added that Kiev was now focusing on restoring ties with Russia. In Brussels, officials said they were ready to continue negotiations with Ukraine in the coming months.
Ukraine's decision was seen as a big victory for Russia, which does not want to lose its big neighbour to the West. In a sign of rapprochement, Russia announced that it would lift its ban on Ukrainian chocolates, which it deemed unsafe just a few months ago.
Meanwhile, thousands of activists rallied in Kiev's two central squares in an echo of the 2004 Orange Revolution, which overturned a rigged election and brought a pro-Western government to power.
"We feel ourselves part of Europe and now the authorities want to take this identity away from us," said Yehor Mnishek, a student from Kiev. "It's like cutting off someone's arm or head."
More rallies were planned. While the protests have been largely peaceful, there have been several scuffles between radical activists and riot police in which tear gas was used.