Donald Trump's former national security adviser Michael Flynn is in discussions with the House and Senate intelligence committees about speaking to their probe into links with Russia in exchange for immunity, his lawyer has said.

Robert Kelner said: "General Flynn certainly has a story to tell, and he very much wants to tell it, should the circumstances permit."

The talks are preliminary and no official offers have been made.

Mr Flynn, who was a member of the Trump campaign and transition, was fired as national security adviser after it was publicly disclosed that he misled vice president Mike Pence about a conversation he had with the Russian ambassador to the US.

Mr Flynn's ties to Russia have been scrutinised by the FBI and are under investigation by the House and Senate intelligence committees.

Other Trump associates have volunteered to speak with investigators, but have not publicly raised the issue of immunity.

Earlier on Thursday, the White House refused to say whether it secretly fed intelligence reports to a senior Republican legislator, fuelling concerns about political interference in the investigation into possible co-ordination between Russia and the 2016 Trump campaign.

Fending off the growing criticism, the administration invited figures from both parties to view classified material it said relates to surveillance of the president's associates.

The invitation came as the New York Times reported that two White House officials - including an aide whose job was recently saved by Mr Trump - secretly helped House intelligence committee chairman Devin Nunes examine intelligence information last week.

Mr Nunes is leading one of three investigations into Russia's attempt to influence the election campaign and Trump associates' possible involvement.

The House panel's work has been deeply undermined by Mr Nunes's apparent co-ordination with the White House.

He told reporters last week that he had seen troubling information about the improper distribution of Trump associates' intercepted communications, and he briefed the president on the material, all before informing Adam Schiff, the committee's senior Democrat.

Speaking on Capitol Hill on Thursday, Mr Schiff said he was "more than willing" to accept the White House offer to view new information, but he raised concerns that Trump officials might have used Mr Nunes to "launder information to our committee to avoid the true source".

"The White House has a lot of questions to answer," he said.

The White House continued to sidestep queries about its role in showing Mr Nunes classified information that appears to have included transcripts of foreign officials discussing Mr Trump's transition to the presidency, according to current and former US officials.

Intelligence agencies routinely monitor the communications of foreign officials living in the US, though the identities of Americans swept up in that collection is to be protected.

Meanwhile, the Senate intelligence committee held its own hearing, a less combative affair in which Russia experts from universities, think tanks and elsewhere described a serious attempt to meddle in the US election - and efforts in France and Germany as well.