Russian security service agents searched a Moscow bank controlled by billionaire tycoon Alexander Lebedev, owner of Britain's Independent and Evening Standard newspapers, on Friday, his aide said.

Former KGB spy Lebedev was not at the National Reserve Bank when several agents from Russia's Federal Security Service, the main successor the KGB secret police, arrived for the search, his aide Artyom Artyomov said.

The FSB agents did not appear to be armed and were not wearing masks, said Artyomov, adding that Lebedev was also concerned by checks by about 130 officials from the central bank which has been going on for a week.

We do not know what the FSB search it is about - you will have to ask them yourself, Artyomov said.

The officials from the central bank are interested in the personal accounts of Alexander Lebedev, including the accounts he uses to finance his newspapers, he said by telephone.

A spokesman for the Federal Security Service said he had no information about the search and declined further comment.

Lebedev has ruffled feathers in the Kremlin in recent years by funding an opposition newspaper and poking fun at Prime Minister Vladimir Putin whom he says must open up the political system or face turmoil in coming years.

Lebedev's bank was raided in 2010 by armed police in masks and he has complained in interviews with Reuters of being under attack by corrupt officials in the law enforcement agencies.

Lebedev, who served in Russian foreign intelligence under diplomatic cover in London, made billions trading stocks and bonds after the 1991 collapse of the Soviet Union.

In an interview in December, he told Reuters he was worth much, much less than Forbes estimate of $2.1 billion, but declined to give a different figure.

(Reporting By Guy Faulconbridge, editing by Rosalind Russell)