ST. PETERSBURG, RUSSIA ? Riot police beat and detained dozens of anti-Kremlin demonstrators Sunday on a second day of protests that tested the weak opposition’s ability to challenge widely popular President Vladimir Putin.

As in Moscow a day earlier, only a few thousand people turned out in St. Petersburg to criticize the government. Opposition leaders called that a heartening response in the face of the huge police forces massed against both rallies.

Putin’s foes said the harsh handling of demonstrators, who included many elderly people, would fuel a growing sense that the leader is strangling democracy ahead of parliamentary elections in December and a presidential vote next spring.

But the opposition is in severe straits. Opinion polls rate Putin as Russia’s most popular political figure by far, thanks to newfound political stability and rapid economic growth fueled by high world oil prices. That popularity has cowed mainstream politicians in parliament and allowed Putin to strengthen the Kremlin’s powers.

His government controls the main television news, allowing his critics few appearances on the prime source of information in the sprawling country. The Rossiya channel on Sunday showed only brief footage of the Moscow protest – after opening with a report on Putin, a judo black belt, attending a martial arts match.

Opposition leaders said they were determined to push ahead. Garry Kasparov, a former world chess champion who has become the most prominent figure in opposition factions loosely allied in the Other Russia coalition, called it “truly amazing” that 2,000 protesters turned out in Moscow to face 9,000 police and troops.

“It shows that the apathy in Russian society is gradually being replaced by very active, vocal protest,” he told The Associated Press.

While television didn’t show much of the confrontations, many ordinary Russians who witnessed the events appeared dismayed by the harsh police crackdown. As an elderly woman comforted a bleeding youth on the ground Sunday, a passer-by remarked, “So this is what they call democracy.”

St. Petersburg authorities gave permission for the protest rally, but kept it under tight control. Helmeted riot police ringed the square, a helicopter hovered noisily overhead and hundreds of police reinforcements waited in trucks and buses lining nearby streets.