KIEV, Ukraine — After the police violently dispersed several hundred protesters in the center of this roiled capital early Saturday, thousands more took to the streets to denounce President Viktor F. Yanukovich’s refusal to sign far-reaching political and free-trade accords with the European Union.

Waving blue-and-yellow Ukrainian flags and the flag of Europe, demonstrators swirled in a huge mass on the cobblestone streets outside St. Michael’s Golden-Domed Monastery, a Kiev landmark dating back hundreds of years, mostly destroyed under Stalinism in 1936 and rebuilt in the 1990’s.

Furious over the failed agreements and enraged by what they said was excessive brutality of the police, protesters shouted, “Kiev rise up!” and “Glory to Ukraine! Glory to her heroes!”

Riot police officers, swinging truncheons and spraying bursts of tear gas, forcibly broke up the crowd in Independence Square, which had been the main protest site for more than a week.