Image copyright AFP Image caption Moscow granting Mr Snowden asylum was no coincidence, a senior US lawmaker says

US intelligence leaker Edward Snowden may have collaborated with Russia, the chairman of the US House Intelligence Committee has alleged.

"I believe there's a reason he ended up in the hands, the loving arms, of an agent in Moscow," Rep Mike Rogers told CBS's "Face the Nation" programme.

Mr Rogers offered no firm evidence to back his theory, and the FBI is said to remain sure Mr Snowden acted alone.

Mr Snowden has been granted temporary asylum in Russia.

The former National Security Agency contractor faces espionage charges over his actions, but denies turning over documents to any foreign government.

'We don't know'

Mr Rogers - a Republican who represents Michigan - told NBC that some of the things Mr Snowden did were "beyond his technical capabilities".

It appeared "he had some help and he stole things that had nothing to do with privacy", such as large amounts of data on the US military, Mr Rogers alleged.

And it would cost the US "billions and billions" to put right its capabilities following the intelligence breaches, he said.

"I don't think it was a gee-whiz luck event that he ended up in Moscow under the handling of the FSB," he added, referring to the Russian state security organisation.

Senator Dianne Feinstein, a Californian Democrat who heads the Senate intelligence committee, told the same programme Mr Snowden "may well have" had help from Russia, but "we don't know at this stage".

Last week, the latest leaks to emerge via Mr Snowden suggested that the US had been collecting and storing almost 200 million text messages every day across the globe, according to the UK's Guardian newspaper and Channel 4 News.

US President Barack Obama has defended the collection of large amounts of data, but has proposed such "metadata" be held by a third party, with the NSA requiring legal permission to access them.

In its reporting of the accusations against Mr Snowden, the New York Times newspaper quoted a senior official with the US Federal Bureau of Investigation as saying that it was still the bureau's belief Mr Snowden had acted alone.