The Citizens for Responsibility and Ethics in Washington said it will file a federal lawsuit against United States President Donald Trump for violating a constitutional provision that prohibits him from receiving anything of value from foreign governments without proper approval, Reuters reported on Monday. The litigation, if seen through, could cause major damage to The Trump Organisation, which includes businesses that lease office space to state-owned companies and rent ballrooms for foreign embassy parties.

The ethics group accused the newly-inducted president of violating the Emoluments Clause, which says that “no person holding any office of profit or trust under [the United States] shall, without the consent of the Congress, accept any present, emolument, office, or title of any kind whatsoever from any king, prince, or foreign state.” Crew has to prove that Trump’s alleged violation caused specific harm to them as the plaintiff, and that his acceptance of revenue from foreign governments falls in the category of gifts.

Trump was also criticised for going against his “America first” slogan. “It was our hope that President Trump would take the necessary steps to avoid violating the Constitution before he took office,” said Noah Bookbinder, executive director of Crew.

The Republican president had tried to reduce criticism about his conflict of interest by announcing that his organisation would be run by his sons, who would not “discuss it” with him. Chief of the Office of Government Ethics Walter Shaub, said Trump’s claims and plans were “wholly inadequate”, The International Business Times reported.

Morgan, Lewis and Bockius, the law firm which represents Trump declined to comment on the case, The Washington Post reported. On Sunday, Trump’s son Eric had said the company had taken more steps to avoid any conflict of interest including donating profits from Trump-owned hotels to the United States Treasury, The New York Times reported.