Minsk, Belarus ? Black-clad riot police clubbed demonstrators as government opponents marched Saturday in defiance of a show of force by authoritarian President Alexander Lukashenko that has drawn U.S. and European Union sanctions.

A week into protests set off by the disputed election that handed Lukashenko a third term, opposition leader Alexander Milinkevich told a crowd of thousands that momentum is growing to bring democracy to Belarus.

“We are starting work against dictatorship, and this work will sooner or later bear its fruit,” he said.

But Milinkevich also urged a monthlong recess in protests, apparently hoping to calm tensions and gain time to build opposition forces, which have fallen far short of the huge outpourings that peacefully overturned governments in Ukraine and Georgia.

The day of confrontation and wildly swinging emotions left two big questions for the former Soviet republic of 10 million people, characterized in the West as Europe’s last dictatorship: How much dissent are the authorities willing to allow and how much support does the opposition have?

Milinkevich spoke at an impromptu rally in a park after hundreds of police blocked protesters from gathering on the central square that had been the focus of anti-Lukashenko demonstrations until riot squads swept in before dawn Friday and arrested dozens of people.

Belarus riot police seal off streets from opposition supporters Saturday in Minsk, Belarus. Rows of riot police on Saturday blocked off a central square where opposition leaders planned a rally over the disputed election in Belarus, pushing crowds away in a massive show of force meant to quash persistent protests against President Alexander Lukashenko, but thousands of demonstrators defiantly gathered in a nearby park.

Demonstrators held flowers, waved the red-and-white flag of the opposition and shouted “Milinkevich!” and “We are not afraid!”

Police didn’t interfere with the 7,000 people in the park, raising hopes that security forces’ long history of violence against dissenters was softening.

But authorities showed their tolerance had limits after part of the rally’s participants marched off toward a jail holding some of those arrested during demonstrations against the March 19 presidential election that the protesters consider fraudulent.

Cheerily chanting “police be with the people” as they passed officers along the way, the crowd of about 3,000 suddenly grew somber when a three-deep phalanx of riot police with shields confronted them at a railroad underpass.

Banging truncheons on shields, the officers advanced on the marchers, causing some to scurry away. Police herded other protesters back along the street, beating some bloody and arresting about 20, as demonstrators shouted “Fascists!”

At least four percussion grenades were detonated, adding to the chaos. Interior Minister Vladimir Naumov later denied the explosions were set off by police, but did not say what caused them.

More than 100 people were arrested throughout the day, said Ales Byalyatsky of the human rights group Vasnya.