US President Donald Trump's administration is drafting an executive order that would allow the CIA to reopen overseas "black sites" that were used to torture suspects after 9/11, US media reported on Wednesday.

The three-page order also would undo many of the restrictions on handling detainees put in place under president Barack Obama to roll back practices authorized during George W. Bush's administration, the New York Times reported.

It would revoke the directive that gives the Red Cross access to all war detainees in US custody, and would order the Pentagon to continue to use the Guantanamo military prison facility "for the detention and trial of newly captured" detainees, including Islamic State jihadists, according to the Times.

The order calls for a high-level review of policies regarding secret overseas Central Intelligence Agency prisons, as well as of enhanced interrogation tactics that have been widely condemned as torture, and are now prohibited by law.

Trump raised the possibility of reinstating such tactics while campaigning for president in 2016, declaring in February that "torture works" and vowing to bring back waterboarding and "much worse."

In December, after meeting with retired general James Mattis, Trump said he was "impressed" with Mattis's argument that building trust and rewarding cooperation by detainees worked better than waterboarding. Mattis has since been sworn in as secretary of defense.

Senator John McCain, a former prisoner of war who was tortured in Vietnam, expressed grave concern about a possible return of the Bush-era enhanced interrogation techniques.

"The president can sign whatever executive orders he likes. But the law is the law," McCain said in a statement.

"We are not bringing back torture in the United States of America." Trump's cabinet picks in the national security realm, including congressman Mike Pompeo, who was recently sworn in as CIA director, made clear during their Senate confirmation hearings that they would not seek a return to the interrogation techniques that Obama halted.

Asked whether he would approve of using techniques outside those outlined in the Army Field Manual, which sets rules for interrogation, Pompeo said "absolutely not."

"I can't imagine that I would be asked that by the president-elect or then president," he said.