Tom Barrack, a long-time personal friend and political supporter of former President Donald Trump, was detained by federal officials in the United States on Tuesday for allegedly operating on behalf of a foreign government, the United Arab Emirates, without registering as a foreign agent.

Barrack, 74, was charged with obstruction of justice in 2019 after lying to federal officials about his ties to a foreign government in an interview.

Matthew Grimes, a friend of Barrack’s, was also taken into custody. Rashid Sultan Rashid Al Malik Alshahhi, a UAE citizen, is still on the loose.

In an indictment released in federal court in New York City, the three were charged with seven counts of crime. The arrests were made in the state of California.

Barrack was a lead speaker at the Republican convention in 2016 at which Trump was nominated as the party’s nominee, and after election served as chairman of Trump’s inauguration committee.

Barrack joins a growing number of people from Trump’s orbit to face legal troubles, ranging from indictment to arrest to sentencing. The most recent case was that of Allen Weisselberg, former Trump Organization chief financial officer, who was arrested and charged with participating in a “sweeping and audacious” tax fraud scheme.

The former US president himself is facing two criminal investigations. In New York, he is being investigated for allegedly manipulating the value of his company’s assets to seek loans or cut tax liabilities. In Georgia, he is being probed for alleged attempts to influence the 2020 presidential election.

Announcing the arrests and indictments, assistant attorney general Lesko said, “The defendants repeatedly capitalised on Barrack’s friendships and access to a candidate who was eventually elected president, high-ranking campaign and government officials, and the American media to advance the policy goals of a foreign government without disclosing their true allegiances.”

The indictment details some of the work that Barrack did to benefit his UAE employers. In May 2016, Barack, who was advising Trump’s campaign, had inserted a favourable mention of the UAE in the candidate’s speech on his energy policy.

After Trump was elected, Barrack allegedly continued advocating for the UAE, and with more influence. The indictment alleges he pushed the candidacy of an individual favoured by the UAE as ambassador to that country.

“In May 2017, Barrack agreed to provide Alshahhi with non-public information about the views and reactions of senior United States government officials following a White House meeting between senior US officials and senior UAE officials,” said the office of the US attorney for the eastern district of New York in a statement.

The 45-page indictment gives specific and granular details of his actions.

Matt Herrington, a lawyer for Barrack, said his client “made himself voluntarily available to investigators from the outset. He is not guilty and will be pleading not guilty today”.