Former FBI director James Comey says both he and his organisation were lied about and defamed by the Trump administration after he was fired while investigating possible links between Russia and Trump's 2016 election campaign team.
Comey has told the US Senate Intelligence Committee he believes this probe was why Trump abruptly dismissed him on May 9 because there was something about the way he was running the probe that was "putting pressure on him, in some way irritating him".
During more than two hours of testimony, Comey also said he believed Trump had directed him in February to drop an FBI probe into the Republican president's former national security adviser Michael Flynn as part of the broader Russia investigation.
Comey gave short, deliberative answers to the senators, while painting a picture of an overbearing president who he did not trust and who pressured him to stop the FBI Flynn probe. But he made no new revelations about any links between Trump or his associates and Russia.
The issue will likely continue to overshadow Trump's presidency, especially as the FBI probe has already ensnared not only Flynn, but also Trump's son-in-law and adviser Jared Kushner. Attorney General Jeff Sessions has had to recuse himself from the investigation.
After Trump fired Comey, the administration gave differing reasons for his dismissal. Trump later contradicted his own staff and acknowledged on May 11 he fired Comey because of the Russia matter.
Comey also told the committee he and the FBI, which was said to be in disarray with poor leadership, were defamed by the Trump administration after the sacking: "Those were lies, plain and simple," Comey said.
Comey would not say whether he thought the president sought to obstruct justice, but added it would be up to special counsel Robert Mueller, who is now investigating the Russia allegations, "to sort that out."
Comey's accusations could further mire Trump's administration in legal difficulties. Mueller and several congressional committees are investigating what US intelligence agencies have concluded was effort by Russia to help Trump win the election by discrediting Democratic candidate Hillary Clinton.
Russia has denied such interference. The White House as denied any collusion with Moscow.
Comey's appearance has attracted massive interest across the US and has been dubbed the "Super Bowl of Washington" with many people holding "watch parties" in pubs, restaurants and living rooms.
Meanwhile, Trump has told supporters: "We're under siege ... but we will come out bigger and better and stronger than ever," he said.
Trump's personal lawyer, Marc Kasowitz, said Comey's testimony proved the president was not under any investigation and there is no evidence a single vote was changed as a result of Russian interference.
Kasowitz denied Trump ever told Comey he needed and expected his loyalty, as Comey said, and also slammed the former FBI chief for saying he leaked details of a conversation with the president.
