US President Donald Trump’s former lawyer Michael Cohen has claimed Mr Trump knew beforehand about a leak of hacked Democratic emails.
In congressional testimony, Cohen also said Mr Trump directed plans for a Moscow skyscraper even during his White House campaign.
In a blistering opening statement, Cohen branded Mr Trump a “racist”, a “conman” and a “cheat”.
Mr Trump hit back: “He is lying in order to reduce his prison time.”
The US president took time out from preparing to meet North Korean leader Kim Jong-un in Hanoi, Vietnam, on Wednesday to lash out in a tweet at his former fixer.
Cohen, 52, will start a three-year prison term in May for the campaign finance violation of paying hush money to one of Mr Trump’s alleged mistresses, tax evasion and lying to Congress.