Protesters clash with riot police during a rally to support EU integration in central Kiev November 24, 2013. Tens of thousands of supporters of Ukraine's European integration flooded central Kiev on Sunday to protest against the government's decision to drop plans to sign a landmark deal with the European Union in Vilnius on November 29 and to revive talks on ties with Russia. [Photo/Agencies]

KIEV - Tens of thousands of Ukrainians, bearing EU flags and chanting "Down with the gang!", marched through the capital on Sunday in a pro-Europe rally denouncing President Viktor Yanukovich's U-turn in policy back towards Russia.

In the biggest street demonstrations in Kiev since the Orange Revolution nine years ago, opposition leaders called on Yanukovich to go ahead with the signing of a landmark agreement with the European Union on November 29 as originally planned.

Prime Minister Mykola Azarov's government, which stunned European leaders on Thursday by announcing it was suspending preparations for signing a key pact with the EU after years of negotiations and reviving trade and economic talks with Russia, should step down, they said.