Former FBI director James Comey is sworn in during a hearing before the Senate Select Committee on Intelligence on Capitol Hill in Washington, DC: Getty Images

Former FBI Director James Comey has been questioned by the special prosecutor probing possible collusion between the Trump campaign and Russia, it has been reported.

Mr Comey, who was fired in May 2017 as Donald Trump became increasingly frustrated by the FBI’s own investigation into possible links to Moscow, was said to have been questioned about a series of memos he kept in which he detailed interactions with the President that “unnerved him”.

In one such memo, which Mr Comey subsequently testified about on Capitol Hill, he noted that Mr Trump had asked him to drop the FBI investigation into former former national security adviser, Michael Flynn.

The fact that investigators led by Special Prosecutor Robert Mueller wanted to talk about those memos and Mr Comey’s concerns, will provide fuel who believe – or hope – the investigation will bring an obstruction of justice finding against Mr Trump.

The disclosure by the New York Times about Mr Comey being questioned came just hours ager the US Department of Justice confirmed that Attorney General Jeff Sessions had also been questioned by the team.

Mr Sessions was questioned for several hours last week, marking the first known time that a member of President Donald Trump’s cabinet has been interviewed as a part of the probe.

The interview, followed Mr Sessions decision to recuse himself from matters related to investigations into the 2016 election, including Justice Department investigations into Russia’s influence – something that deeply angered Mr Trump. At one point, it was widely reported Mr Trump was set to replace Mr Sessions as he believed his actions had put in motion Mr Mueller’s probe.

Mr Sessions was one of the first sitting members of Congress to publicly support Mr Trump’s run for president, and had served as a high profile surrogate and adviser for the campaign.