The meetings are documented in a prepared statement by Mr Comey
Former FBI Director James Comey has revealed that US President Donald Trump asked him to drop an investigation into former National Security Adviser Michael Flynn.
The revelation is contained in a written statement that Mr Comey will deliver on Thursday to a US Senate hearing investigating allegations of collusion between the Trump campaign and Russian officials.
Mr Comey, who was fired by the president a month ago, describes a meeting at the White House on Valentine's Day during which Trump brought up Mr Flynn.
"He is a good guy and has been through a lot," Mr Comey reports Trump as saying. "I hope you can see your way clear to letting this go, to letting Flynn go. He is a good guy. I hope you can let this go."
Mr Flynn resigned after it was revealed he had misled the White House over contacts with the Russian ambassador to the US.
Of Trump's words, Mr Comey writes: "It was very concerning, given the FBI's role as an independent investigative agency."
The former director also describes a one-on-one dinner with Trump at the White House a few days after the inauguration.
He said Trump told him: "I need loyalty, I expect loyalty."
"He then said 'I need loyalty.' I replied 'You will always get honesty from me'. He paused and then said 'That's what I want, honest loyalty.' I paused, and then said 'You will get that from me'.
"It is possible that we understood the phrase "honest loyalty" differently but I decided it wouldn't be productive to push it further."
Mr Comey said that during the dinner Trump asked him if he wanted to stay on as FBI director and he became concerned that the president was trying to create "some sort of patronage relationship".
In his testimony, Mr Comey also confirms that, at a meeting at Trump Tower before the inauguration, he had told the then president-elect he was not personally the subject of an investigation.
In subsequent phone calls, he said, the president had repeatedly said: "We need to get that fact out."
"He asked what we could do to 'lift the cloud'."
Mr Comey described his efforts to document his meetings with Trump: "To ensure accuracy, I began to type it on a laptop in an FBI vehicle outside Trump Tower the moment I walked out of the meeting".
"Creating written records immediately after one-on-one conversations with Mr Trump was my practice from that point forward."
The explosive details contained in Mr Comey's written testimony are sure to be questioned during both the open and closed sessions of the Senate committee.
Mr Trump's administration has been dogged by claims that his campaign benefited from Russian attempts to meddle in November's election.
He has repeatedly dismissed the claims as "fake news". Mr Comey was fired as FBI chief by Mr Trump on May 9th.