Washington, Jul 22 (IANS): President Donald Trump's ex-lawyer Michael Cohen has sued the US attorney general for a so-called 'gag order'.

Cohen said he was sent back to prison as retaliation for writing a tell-all book that reportedly details alleged racist comments made by the president, the BBC reported.

Cohen had been released in May from a three-year sentence for charges including Trump campaign finance violations, due to coronavirus.

The suit claims Cohen's re-arrest violates his right to free speech.

The Bureau of Prisons director is named along with US Attorney General William Barr in the lawsuit filed by Cohen's lawyers and the American Civil Liberties Union (ACLU) on Monday. The lawyers have requested Cohen's immediate release from prison.

The 53-year-old has a history of respiratory issues and is vulnerable to Covid-19, they said.

Cohen was taken back into custody on July 9, after authorities said he refused the conditions of his home arrest. Days earlier, on July 2, Cohen tweeted that was "close to completion" of a tell-all book.

In court documents filed Monday night, Cohen wrote that his book - tentatively titled Disloyal: The True Story of Michael Cohen, Former Personal Attorney to President Donald J Trump - will describe first-hand experiences with Trump and his family, the US media reported.

The book will "provide graphic and unflattering details about the President's behaviour behind closed doors," the documents said.

Among these details are descriptions of "the President's pointedly anti-Semitic remarks and virulently racist remarks against such Black leaders as President Barack Obama and Nelson Mandela, neither of whom he viewed as real leaders or as worthy of respect by virtue of their race".

Cohen's attorneys said his constitutional rights were violated when probation officers asked him to sign a gag order that would prohibit him from "speaking to or through any media of any sort", including social media or publishing a book, as a condition of his prison release.

When Cohen asked for clarification about this "unusual agreement", he was handcuffed and returned to federal prison in Otisville, New York, his lawyers said.

"The government cannot imprison Michael Cohen for writing a book about President Trump," said ACLU Speech, Privacy and Technology Project director Ben Wizner.

"The gag order that the government sought to impose on Mr Cohen was an unconstitutional prior restraint, and his continued imprisonment is part of a dangerous pattern of retaliation against Trump critics."

The Department of Justice did not immediately respond to a request for comment from the BBC.

The White House has not yet commented on the allegations.

Cohen has served a year of his three-year sentence.

The former fixer admitted to lying to Congress about a Trump Tower project in Moscow, and to campaign finance violations for his role in making hush money payments to women alleging affairs with Trump. He also admitted to other tax and bank fraud charges unrelated to the president.