President Donald Trump on Thursday described Michael Cohen as a "weak person" and accused him of lying in court to get a reduced sentence shortly after his former lawyer offered bombshell revelations in court.

Cohen on Thursday morning pleaded guilty to lying to Congress about his involvement in discussions to build a Trump Tower in Moscow.

Court documents made public on Thursday said Cohen discussed the Trump Tower Moscow plan with the president and his family multiple times.

President Donald Trump on Thursday described Michael Cohen as a "weak person" and accused him of lying in court to get a reduced sentence, lashing out at his former lawyer after Cohen offered bombshell revelations in court.

"He’s a weak person. ... He's lying to get a reduced sentence," the president told reporters.

When asked why he would hire Cohen if he's an untrustworthy and weak person, Trump said "a long time ago, he did me a favor."

Cohen on Thursday morning pleaded guilty to lying to Congress about his involvement in a plan to build Trump Tower in Moscow.

Read more: Michael Cohen reaches a new plea deal with Mueller and is expected to give dozens of hours of testimony that could damage Trump

The developments came as Cohen entered a new plea deal with special counsel Robert Mueller, who is leading an investigation into Russian election interference. Cohen is expected to give dozens of hours of testimony that could implicate Trump as part of the new deal.

Court documents made public on Thursday said Cohen discussed the Trump Tower Moscow plan with the president and his family multiple times.