Police search Putin opponents' homes before rally

An opposition activist attends a protest rally to defend Article 31 of the Russian constitution, which guarantees the right of assembly, in Moscow May 31, 2012. The sheet of paper attached to the woman's face reads ''I keep silent''.

MOSCOW (Reuters) - Russian police and investigators searched the homes of several prominent opponents of President Vladimir Putin on Monday, one day before a protest opposition leaders hope will draw tens of thousands of people.

Russia's main investigation agency said it planned to conduct about 10 searches in connection with a criminal probe into violence against police at a protest held in Moscow on the eve of Putin's inauguration on May 7.

Prominent opposition leaders Alexei Navalny and Sergei Udaltsov were among those whose Moscow apartments were being searched, the Federal Investigative Committee said on its website.

"There's a search going on at my home," Navalny, an anti-corruption blogger and one of the organizers of protests sparked by allegations of fraud in a December parliamentary election won by Putin's party, said on Twitter.

"They practically cut out the door," he wrote. Ekho Moskvy radio said police had prevented Navalny's lawyer from entering.

Putin won a six-year presidential term in March despite a wave of protests which drew tens of thousands of people to the streets, demonstrating significant opposition to his rule, particularly among middle-class city dwellers.

Opposition leaders plan to hold the first big protest in Moscow since his inauguration on Tuesday.

The Interfax news agency reported that at least one of the opposition leaders, Udaltsov, was summoned for questioning on Tuesday, potentially interfering with his ability to attend the protest.

Putin signed a law on Friday that drastically increased fines for violations of public order at street demonstrations in what opponents said was an effort to silence dissent.

(Writing by Steve Gutterman; Editing by Robin Pomeroy)