The former CIA director, John Brennan, said there were enough contacts between members of the Trump campaign and Russian intelligence services by last summer to justify an investigation by the FBI.

Brennan testified before the House Permanent Select Committee on Intelligence on Capitol Hill on May 23, and gave account to date of the scale of effort to combat Russian operations trying to affect the outcome of 2016 elections.

He also confirmed the CIA set up a special group with the NSA and FBI in late summer to investigate the extent of Russian intervention in the presidential election and warned Alexander Bortnikov, head of Russian intelligence agency, in a call to stop interfering. Bortnikov told Brennan he would pass on the message to russian president, Vladmir Putin.

Daniel Coats, Director of National Intelligence, declined to confirm or deny a report that say president Trump pressure him to publicly deny there was evidence of collusion between his campaign and the Russian government.

"We discuss a number of topics on a very regular basis. I have always believed that given the nature of my position and the information that which we share, it's not appropriate for me to comment publicly on any of that", Coats said.

"So, on this topic as well as other topics, I don't feel it's appropriate to characterize discussions and conversations with the president," he added.

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