President Donald Trump's former personal lawyer, Michael Cohen, is postponing his Feb. 7 testimony to the U.S. Congress because of threats against his family from Trump, his adviser said on Wednesday.

Cohen, who has pleaded guilty to crimes he committed while working on Trump's 2016 election campaign and is cooperating with investigators, had received "ongoing threats against his family from Trump" and Trump's lawyer, Rudy Giuliani, the adviser, attorney Lanny Davis, said in a statement.

Trump called Cohen a "rat" in a tweet last month for cooperating with prosecutors. Cohen had been Trump's self-described longtime "fixer" and once said he would take a bullet for the New York real estate developer.