The top Democrat on the House Intelligence Committee looking into potential ties between associates of President Donald Trump and Russia has said he has “profound concern” about the way intelligence materials were possibly shared with the panel's chairman.

Two White House officials reportedly played a role in giving Republican Devin Nunes the intelligence reports that formed the basis for a statement that Mr Trump transition team members had information “incidentally” picked up.

Adam Schiff, a California Democrat, said he has “a lot of unanswered questions” about the process. He raised concerns about why, if the White House did give Mr Nunes the information, it shared the reports with the congressman rather than going directly to the White House.

“Why all the cloak and dagger stuff?” Mr Schiff asked.

The White House refused to discuss the report, which first appeared in The New York Times. Asked if he would tell reporters if the report was wrong, White House Press Secretary Sean Spicer said he was “not going to get into it.”

However, the administration did invited legislators from both parties - and both the Senate and House investigations into Russia - to view classified material it said relates to surveillance of the president's associates.

The White House's invitation letter came amid the quickly rising storm over Mr Nunes. The House panel's work has been deeply, and perhaps irreparably, undermined by Mr Nunes' potential coordination 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 Mr Schiff.

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 may have used Mr Nunes to “launder information to our committee to avoid the true source.”

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The furore over the White House came as public hearings for the Senate investigation into Russia’s interference with the 2016 presidential election began, with Senator Mark Warner noting “this is not fake news. This is actually what happened to us.”

Mr Warner is the Vice Chair of the Senate Intelligence Committee in charge of the investigation into not only Russian interference but any ties President Trump’s campaign and transition teams may have had with Russia during the election.

Three main witnesses appeared before the committee as part of a “primer” on what Russia is capable of and what they could have done to the 2016 election.

Russian history was discussed as a means of understanding their current and future capabilities. Roy Godson, a professor at Georgetown University, said regarding how Russia were able to make such advances in cyber attacks: “they were able to take enormous advantages” while the US was not paying as much attention to the matter.

Dr Eugene Rumer, Director of Russia and Eurasia Program at the Carnegie Endowment for International Peace, also explained that Russia’s defence costs are far less than the US and the tools they use are “cheap.”

“A handful of cyber criminals costs a lot less than an armored brigade,” Mr Rumer added.

Chairman of the committee Republican Senator Richard Burr confirmed with Mr Rumer that there was indeed “evidence of [Russia’s] ability to build up or destroy the character of [candidates].”

Mr Rumer said fake news sites detailing the “failures” of Angela Merkel - like allowing Syrian and other refugees into Germany - were popping up everywhere in order to discredit her in the eyes of the public.

“Staggering” is how Mr Rumer described Russian influence on the French election. He said Russian President Vladimir Putin hosted the far-right candidate in Moscow “almost with a smirk. Like he was saying ‘we don’t interfere, but we have the right to engage any candidate in the process.’”

​Clint Watts, Senior Fellow at the Foreign Policy Research Institute Program on National Security, also noted that Russian interference in elections has the goal of “creating confusion information sources by blurring the lines between fact and fiction.”

Mr Watts also has a list of recommendations for combating such foreign influence but Mr Burr said the committee noted that the list has not been heeded and that the US “response to date has been woefully short of what needs to be.”