MADRID, April 17 (Reuters) - A Spanish judge considering possible criminal action against six former Bush administration officials for torture at the U.S. prison at Guantanamo Bay defied pressure to drop the case on Friday.

But Judge Baltasar Garzon, internationally known for trying to extradite former Chilean dictator Augusto Pinochet, accepted that he might not personally take charge of any eventual criminal investigation into officials including former U.S. Attorney General Alberto Gonzales.

On Thursday, Spain's attorney general said Garzon should dismiss the complaint brought by human rights lawyers calling for the officials to be prosecuted.

In a ruling on Friday, Garzon ignored this advice but also avoided a direct confrontation with the attorney general's office by submitting the case to a lottery system which will now assign it at random to one of the six high court judges.

"Let it be assigned to the corresponding court," Garzon said in the ruling.

The judge who gets the case will now have to decide whether to go ahead of it. Under the system, Garzon will have a one in six chance of getting the case back.

Under Spanish law, jurisdiction can be claimed in the case because five Spanish citizens or residents who were prisoners at U.S. prison camp in Guantanamo Bay, Cuba, say they were tortured there.

Attorney General Candido Conde-Pumpido said the case should not be accepted because if anyone should be investigated for torture at Guantanamo it should be those who carried it out.

U.S. President Barack Obama also spoke out against the proposed investigation on Thursday, saying he would prefer not to focus on past events at Guantanamo, which he has promised to close.

The other Americans named in the accusation are William Haynes II, former general counsel for the Department of Defense; John Yoo, the former Justice Department lawyer who wrote secret legal opinions saying President George W. Bush had the authority to circumvent the Geneva Conventions; Douglas Feith, former undersecretary of defence for policy; Jay Bybee, Yoo's former boss at the Justice Department's Office of Legal Counsel; and David Addington, chief of staff and legal adviser to ex-Vice President Dick Cheney.