MANNHEIM, Germany - The U.S. military judge hearing the Abu Ghraib abuse case said prosecutors had until Sept. 17 to file charges against top military intelligence commanders or he would consider forcing them to testify under a grant of immunity.

Judge Col. James Pohl also rejected a request from the attorney for Spc. Javal Davis for Secretary of Defense Donald Rumsfeld and his deputy Stephen Cambone to submit to an interview, but said it could be brought back if the defense can fill in some of the gaps.

"There's got to be some links in that chain," Pohl said.

Davis and the five other military police accused of abusing prisoners at the Baghdad prison insist they were following orders from military intelligence officers and civilian contractors.

Davis' civilian attorney, Paul Bergrin, asked the court to grant immunity from prosecution to Col. Thomas Pappas, the military intelligence commander at Abu Ghraib, and several other officers who may have known of the abuse but have refused to talk to investigators citing their right to avoid self-incrimination.

Such testimony could broaden the case beyond the six low-ranking Army reservists and raise the possibility that intelligence officers and others within the military encouraged the abuse to gain information about Iraqi insurgents battling U.S. troops.

A grant of immunity could remove a key obstacle to their testimony, but prosecutor Maj. Michael Holly argued that the officers themselves could face charges after the military completes a report into the role of military intelligence at detention facilities, which is expected to be presented to Congress early next month.

The judge gave the prosecution until Sept. 17 to convince him that they should not be compelled to testify. Pohl made it clear, however, that if the government does not intend to file major charges against the officers by then, he would probably grant them immunity to testify.

"This would appear to be critical information to the defendants ... that this was condoned by the higher-ups," Pohl told the prosecutors. "You know where this is going - it's either pay me now or pay me later."

However, Pohl said Davis' defense had not presented enough evidence to establish that comments allegedly made by Rumsfeld authorizing rough treatment of detainees at Guantanamo Bay had resulted in abuse at Abu Ghraib.

"I'm not saying there is not a link, I'm saying at this point you haven't shown me sufficient evidence," Pohl said.

The second day of pretrial hearings for four soldiers at a U.S. military barracks in Germany also brought Davis' admission that he initially lied to a military investigator by saying he did not take part in the maltreatment.

Davis said he was exhausted after a grueling day manning a watchtower and made the false statement because he wanted the Jan. 14 interview to end. He said he went back to investigators the next day and confessed.

"I was dishonest about the things I was accused of," Davis told the hearing at a U.S. military barracks in Mannheim. "I wanted to maintain my integrity."

Davis' lawyer pounced on testimony by the military investigating agent, Manora Iem, that he was also tired when he interviewed Davis.

"You knew that you were tired that day and yet you put nothing in the report," defense lawyer Paul Bergrin challenged Iem during sharp cross-examination.

Iem said he took no notes during the interview but drafted a five-page report of Davis' statements which the soldier signed. Iem said Davis told him "that he had seen things that were immoral" and described several of them.

Davis, of Roselle, New Jersey, is among seven U.S. army reservists charged in the prison abuse scandal that erupted last spring when photos became public, causing worldwide outrage about the physical abuse and sexual humiliation of inmates.

All were in Iraq as members of the 372nd Military Police Company, based in Cresaptown, Maryland. One of them, Spc. Jeremy Sivits, pleaded guilty May 19 and was sentenced to a year in prison.

Davis appeared relaxed and greeted reporters today as he entered the heavily secured courtroom. Before the session began, he went to the court's sketch artist to look at how he was being drawn.

Davis is among soldiers accused of piling naked Iraqi prisoners into a human pyramid and photographing themselves standing by, grinning and giving the thumbs-up sign. Davis, Spc. Charles Graner and Ivan "Chip" Frederick II - another defendant to be heard today at Mannheim - also allegedly jumped on the pile of prisoners.

Frederick, in a statement given to The Associated Press on Monday, said he would plead guilty to some charges, but did not specify which. He is charged with maltreating detainees, conspiracy to maltreat detainees, dereliction of duty and wrongfully committing an indecent act.

A Pentagon report into the scandal has found U.S. defense leaders at least partly to blame for the abuse of detainees at Abu Ghraib and other prisons, the New York Times reported today

The report, to be officially released today, concluded that commanders failed to address overcrowding at the prisons and handed off oversight of prisoners to subordinates.

It faults top defense leaders - including the military's Joint Staff and Lt. Gen. Ricardo Sanchez, the former top U.S. commander in Iraq - for inadequately supervising interrogation techniques and other policies at several prisons in Cuba, Afghanistan and Iraq, the Times said, citing unnamed defense officials.