Clashes have broken out between police and protesters outside the Ukrainian parliament in Kiev after a controversial vote to give greater powers to separatist regions in the east.

The decentralization of power was a condition of a truce signed in February aimed at ending the fighting between Ukrainian government troops and Russia-backed separatists that has left more than 6,800 dead. But many Ukrainians oppose changing the constitution, saying that threatens the country's sovereignty and independence.

A total of 265 deputies in the 450-seat parliament voted Monday to approve the changes proposed by Ukrainian President Petro Poroshenko. Three parties that are part of the majority coalition in parliament, however, opposed the constitutional changes, which face a final vote Tuesday.

Outside the parliament building, riot police faced off against hundreds of protesters.