The Pentagon has scrapped a rule that required US military judges overseeing tribunals at Guantanamo Bay to stay permanently at the American base in Cuba, officials said Friday.

The rule, imposed last month, was meant to speed up the pace of the trials for Guantanamo inmates facing terror charges.

But defense lawyers for five inmates accused of plotting the September 11, 2001 attacks argued the order was evidence of government interference in their cases. The presiding military judge, James Pohl, also voiced concerns about the appearance of government meddling and suspended all pre-trial hearings for the accused 9/11 plotters on Wednesday.

Deputy Defense Secretary Robert Work rescinded the rule in a memo on Thursday, Pentagon press secretary Rear Admiral John Kirby told reporters.

Work was aware that "there was perhaps an inappropriate perception formed by that decision" and cancelled the change to safeguard the independence of the military commissions, Kirby said.

"Any such regulation must preserve the independence of the military commission judiciary in both fact and appearance," Work wrote in the memo, which was released Friday.

The military commissions are special courts set up in 2001 to try some Guantanamo detainees on terror charges.

The tribunals have been sharply criticized by human rights groups as lacking the legal protections of regular courts and have produced only a handful of convictions so far.

The legal process for the commissions may not operate with "the speed or maybe even the efficacy that some would like to see it done," Kirby said. But the Pentagon believes the commissions provide fair, open and transparent trials that can hold suspects to account, he said.