The protesters set fire to heaps of tires, sending clouds of black smoke billowing across the city center square, known as the Maidan. Protesters camped there played a pivotal role in demonstrations that chased former president Viktor Yanukovich from power earlier this year.
Armed riot police moved onto the square as protesters - some of them in combat fatigues and masks and waving clubs - threw bottles and paving bricks at municipal workers who had been dispatched to dismantle the tents and barricades.
Maidan activists argue with Ukrainian National Guard soldiers in front of a barricade.
Many protesters, including self-defense militias, have taken down their tents and returned to their homes since the election of Petro Poroshenko as president at the end of May. But many barricades have remained in place, along with makeshift shrines to the 100 or so protesters killed by police sniper fire, and a few hundred people are still camped out on the Maidan.
An Orthodox priest throws a tire as activists clash with fighters from the Kiev-1 volunteer battalion on Independence Square in Kiev.
An injured activist smokes a cigarette after clashes with a special forces police battalion in Independence Square.
A Maidan activist runs away from a burning barricade.
Kiev's new authorities have made clear they would like the capital city back to normal, with traffic moving freely, ahead of an expected parliamentary election at the end of October.
A Maidan activist shouts slogans during the protest. The police and city workers eventually withdrew, leaving the situation unresolved.