About three dozen people were arrested attending an unauthorized demonstration in the Russian capital on Sunday, one week after several hundred protesters were arrested at nationwide anti-government rallies.

There was a heavy police presence in central Moscow as authorities sought to prevent a repeat of last week's demonstrations, the biggest anti-government protests in five years.

Police moved quickly to arrest 29 people as they attempted a march on Triumphalnaya Square, and another seven others were detained at Manezhnaya Square, TASS news agency reported, citing police numbers.

Sunday's attempted march drew about 100 protesters, far fewer than the thousands across the country who came out onto the streets last weekend.

Opposition leader Alexei Navalny was arrested for 15 days and hundreds of others taken into custody after attending dozens of anti-corruption rallies, most of them unauthorized, from the Far East to Moscow on March 26.

Navalny said through a spokesperson he had nothing to do with organizing this Sunday's protests.

The size of last weekend's protest raised questions about whether President Vladimir Putin would address protesters' concerns or put down any dissent. On Thursday, he made clear he would allow no challenge.

''Everybody should act in political processes within the framework of the law. All those who go outside this law should bear punishment in accordance with Russian law," Putin said Thursday.

An anti-corruption campaigner, Navalny called last weekend's protests after his foundation published a report earlier this month accusing Prime Minister Dmitry Medvedev of owning mansions, yachts and vineyards through a shadowy network of nonprofit organizations supported by oligarchs. A YouTube video Navalny posted outlining the allegations has been viewed 16 million times.

cw/rc (AFP, AP, dpa)