SAN JUAN, Puerto Rico — A military judge at Guantanamo on Thursday rejected a White House request to suspend a hearing for the alleged mastermind of the USS Cole bombing, creating an unexpected challenge for the administration as it reviews how America puts suspected terrorists on trial.

The judge, Army Col. James Pohl, said his decision was difficult but necessary to protect “the public interest in a speedy trial.” The ruling came in the case against Abd al-Rahim al-Nashiri. The bombing of the Navy destroyer in 2000 in the harbor of Aden, Yemen, killed 17 U.S. sailors.

The judge’s decision seemed to take the Pentagon and White House by surprise.