Russian investigators have raided the office of anti-corruption campaigner and leading opposition figure Alexei Navalny after he was taken for questioning by a dozen policemen who intercepted him outside his Moscow apartment building.

The interrogation and raid appeared aimed at increasing the pressure on Mr Navalny, a vehement foe of President Vladimir Putin. He has refused to stay silent despite a criminal conviction that has kept him under house arrest and sent his brother to prison.

The Kremlin has been reluctant to jail Mr Navalny to avoid turning him into a martyr, but has also seemed determined to prevent him from playing any role in stirring up discontent. The raid suggested renewed efforts to shut down his corruption-fighting foundation and stop its exposure of official abuses.

A court in late December convicted Mr Navalny of fraud and gave him a three and a half year suspended sentence, but said that until his appeals were exhausted he must remain under house arrest. He has been allowed to leave his home in recent days, but has been followed by officers posted outside his door.

Mr Navalny said he was met this morning by 12 police officers and taken to the federal Investigative Committee, which had summoned him for questioning about his anti-corruption activities. He said the whole thing was like a movie.

"Three police are with me in the car and three in plainclothes in the car next to us," he said on Twitter. "Too bad I didn't bring my dark glasses."

A couple of hours later, investigators backed by masked policemen with automatic rifles raided his foundation's offices. The director, Roman Rubanov, said all of the computers and telephones had been seized.

One of Mr Navalny's employees, Georgy Alburov, who was outside the office, said the search continued into the evening and his colleagues were allowed to step out to smoke but were unable to leave. He said the investigators produced a search warrant referring to the alleged theft of a painting.

The Investigative Committee said the search was in response to a complaint from lawmaker Mikhail Degtyarev, who ran alongside Mr Navalny in the 2013 mayoral election. Mr Degtyarev lost the election badly while Mr Navalny finished a strong second behind Kremlin candidate Sergei Sobyanin.

The lawmaker had found it suspicious that Mr Navalny's foundation spent about 60% of its budget on payroll, the agency said in a statement carried by Russian news agencies. This seemingly absurd complaint drew a sarcastic tweet from Mr Navalny, who said: "And what, excuse me, should we have spent this on?"

His lawyer, Olga Mikhailova, said he had refused to answer questions from investigators during the interrogation because he believed their aim was to bring criminal charges against him, the Tass news agency reported.

The previous night, police detained 13 people among about 100 who held a protest in central Moscow in support of Mr Navalny and his brother. Scuffles broke out when they were confronted by a much larger group of pro-Kremlin activists.

In St Petersburg, about 300 people rallied peacefully in support of Mr Navalny.

He played a leading role in anti-Putin demonstrations in Moscow in 2011 and 2012 that drew hundreds of thousands. But after Mr Putin's election to a third term, the Kremlin moved steadily to intimidate and marginalise all opposition.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.