Clashes amid huge Ukraine protest against U-turn on EU
A huge rally has been taking place in the Ukrainian capital to oppose a government decision not to sign a deal on closer EU ties, despite a ban.
Casualties were reported on the fringes of the rally after clashes near the office of the president.
Police used tear gas and stun grenades to repel a group advancing on police lines and throwing large stones.
Elsewhere in the city centre, protesters stormed the city council building and occupied it.
Vast crowds rallied on Kiev's Independence Square, defying a ban imposed a day earlier. Estimates of the numbers ranged from around 100,000 to more than 350,000.
The mainstream opposition and its leaders said they had nothing to do with those engaged in violence near the presidential headquarters, and that it was the work of "provocateurs".
Protesters are demanding the resignation of President Viktor Yanukovych's government and new elections. President Yanukovych says Russian pressure was behind his decision not to sign the deal.
The leader of the opposition Fatherland party, Arseny Yatsenyuk, told a news conference that the plan for Monday was to start a picket outside the Ukrainian government building. He said a no-confidence motion had been submitted to parliament.
A group of people tried to approach President Yanukovych's headquarters, some of them commandeering a bulldozer to break through police lines.
Police used tear gas and stun grenades to force back the crowd, who responded by throwing bricks or paving stones.
The Associated Press news agency said that dozens of people were taken away by ambulance with what appeared to be head injuries. At least three journalists were reported to have been injured.
A police spokeswoman said about 100 police were injured in the clashes near the presidential headquarters.
A message posted on the Interior Ministry's Facebook page accused some 300 members of the radical Brotherhood organisation of involvement in the trouble.
About a kilometre away, at the city council building, protesters broke windows to get inside the premises.
Members of the nationalist Svoboda party occupied the building and held meetings, Reuters news agency reported.
The protesters chanted "Kiev is ours" and hung a Ukrainian flag in the window.
The protests started more than a week ago after President Yanukovych suspended preparations for signing an EU association agreement that would have opened borders to goods and set the stage for an easing of travel restrictions.
Mr Yanukovych argued that Ukraine could not afford to sacrifice trade with Russia, which opposed the deal.
The Ukrainian president has said he is "deeply outraged" by events at opposition protests in Kiev.
He was speaking after police violently dispersed an opposition camp on Saturday. Several Western countries condemned the police intervention.
Jailed opposition leader and ex-Prime Minister Yulia Tymoshenko earlier urged Ukrainians "not to leave the authorities' actions unanswered".
She has been on hunger strike since Monday over the failure to sign the EU agreement.