Russian activists' homes raided

Police told those who were searched that they had to appear for questioning Tuesday morning, most likely preventing them from joining the march and rally they organized, which begins at noon.

The raids came after the Russian parliament hurriedly passed a law raising fines for protesters by 120 percent, to as much as $48,000 for organizers of a rally where laws are broken. Putin signed the law Friday and it went into effect Saturday, just in time for Tuesday's march.

The protest movement coalesced in December over anger at parliamentary elections that were described as rigged. Those elections were followed by March's presidential vote, which brought Putin back to the presidency for a six-year term. He had been prime minister, following two earlier four-year terms as president.

The raids immediately set off a firestorm on Twitter, where they were compared to Stalin's purges of 1937. The hashtag Hello 1937 quickly trended to the top of Russian Twitter - though these searches were far different than 1937, when henchmen knocked in the middle of the night, and neighbors looked away. These searches were carried out with witnesses, including journalists summoned by Twitter alerts, although they began around 8 a.m. in the middle of a long weekend preceding Russia Day on Tuesday, a national holiday celebrating the declaration of sovereignty in 1990.

Navalny documented the search of his home, sending out photos on his phone of police searching his children's room and confiscating a T-shirt bearing the slogan he popularized denigrating Putin's United Russia party as the Party of Crooks and Thieves.

A spokesman for the Russian Investigative Committee said the searches were connected to a criminal investigation of a demonstration May 6, on the eve of Putin's inauguration, when police and protesters clashed.