The U.S. Embassy in Ukraine has called for an end to ongoing violent confrontations between protestors and police in Kyiv, urging a calm and political dialogue.

"The United States Embassy calls for an end to ongoing violent confrontations between protestors and police in Kyiv. We urge calm and call on all sides to cease any acts provoking or resulting in violence," the Embassy said in a statement posted on its official Web site on Sunday.

"We further urge the Government of Ukraine to immediately start negotiations with all sides to resolve the political standoff, address protestors' concerns, and prevent violence from spreading," the statement reads.

"Violence only serves to foster fear and confusion, and distracts from the need for a political solution, which is the best way to carry out the will of the Ukrainian people," the statement reads.

Clashes between anti-government protesters and police in the center of Kyiv started on Sunday afternoon.

A people's assembly on Independence Square, or Maidan Nezalezhnosti, started at noon on Sunday. Opposition parties' leaders announced their action plan to form people's government. After the assembly was over, a large number of Euromaidan and Automaidan protesters moved along Khreschatyk Street to the Dynamo stadium. They were attempting to get to the Verkhovna Rada (Parliament) building. Earlier, an Automaidan activist said at the people's assembly that Automaidan protesters' cars were going to drive to the parliament's building and stay there in protest against the laws that were passed by parliament on January 16, 2014 and that limit rights to freedom of speech and peaceful assembly.

Later on violent rioters launched attacks on a line of riot police on Hrushevskoho Street (close to the Dynamo stadium). Unidentified people set on fire a bus used by the police as a cordon. Sticks, baseball bats, stun and tear gas grenades were used during the clashes.

The leaders of the three opposition factions in parliament – the Batkivschyna faction, the Svoboda party, the UDAR Party, reiterated during their address on Independence Square on Sunday that their action plan is peaceful. They urged protesters to leave Hrushevskoho Street.