Mr Comey told the US House Intelligence Committee: "This work is very complex, and there is no way for me to give you a timetable for when it will be done".
"I do believe he owes us that explanation".
Kim Darroch, the British ambassador to the United States, also helped in alleviating the tense situation between the two nations by speaking with Sean Spicer last week and, according to a spokesperson for Prime Minister Theresa May, the White House chose to back off from their claims of illegal wiretapping.
British Government's Communications Headquarters (GCHQ) in Cheltenham, Gloucestershire.
The Senate's top Democrat says that President Donald Trump "severely damaged his credibility" with Twitter postings claiming that former President Barack Obama ordered wiretaps of him. "The Department of Justice has asked me to share with you that the answer is the same for the Department of Justice and all its components: The department has no information that supports those tweets".
Panetta, who also has served as President Bill Clinton's chief of staff and as director of the Office of Management and Budget in his administration, said Trump's agenda will depend on developing a consensus in Congress. On Fox, he said he did not believe it occurred.
Trump even told the press that if they wanted to get to the truth they should speak with Fox News and not him.
Meanwhile, the directors of the Federal Bureau of Investigation and National Security Agency were due to speak publicly today about the claims of alleged links between Russian Federation and president Trump's campaign.
Trump tried to joke with Merkel about the situation, saying that they "have something in common", in that they have both been victims of United States government wiretapping.
"I don't know the basis for President Trump's assertion", US Senator Susan Collins, a Republican, said on NBC's Meet the Press on Sunday.
The wiretapping allegation is seen by many as a controversy entirely of Trump's own making.
A separate tweet referenced James Clapper, the director of national intelligence under President Barack Obama, who has said that Trump's allegation that Obama wiretapped Trump Tower is false.
Comey has been invited to testify, along with the director of the National Security Agency, Michael Rogers.