Michael Cohen has postponed giving evidence to Congress after Donald Trump threatened him and his family, his adviser said.
The threats against the former “fixer” for the president were “ongoing”, attorney Lanny Davis said in statement on Wednesday.
Responding to the claims, the US leader said: "I would say he's been threatened by the truth.”
Mr Cohen was due to appear before the House Oversight and Reform Committee on February 7.
The committee is investigating hush-money payments made during the 2016 presidential campaign to silence women who claimed to have had sex with Mr Trump.
The US leader denies having an affair.
Mr Cohen received "ongoing threats against his family from Trump" and Mr Trump's lawyer Rudy Giuliani, the adviser said
Mr Cohen has pleaded guilty to crimes including campaign finance violations during Trump's election campaign.
He said he and is cooperating with investigators.
In a Fox News interview this month, the president suggested he had damaging information on Mr Cohen's father-in-law.
"That's the one that people want to look at," Mr Trump said in the interview.
Chair of the Committee on Oversight and Reform Mr Cohen’s concerns for the safety of himself and his family were understood.
But lawmakers said they would not "let the President’s tactics prevent Congress" from getting to the truth.
"I promise you that we will hear from Mr Cohen. ... Whatever we have to do to get him here, we're going to do it.”
