The USS Iowa steamed toward its home port Saturday as naval investigators continued to search for clues to what caused the explosion that claimed 47 lives. The Washington Post reported some sailors died of asphyxiation.

The World War II battleship was expected to arrive in Norfolk at 5:40 p.m. EST Sunday.Lt. Cmdr. Alan Dooley said no cause of death has been announced for any sailors, but the Post reported that seamen in the upper chambers of gun turret No. 2 died instantly in the explosion while those in the lower levels were suffocated as the blast siphoned off their oxygen.

"We have not announced any causes of death," Dooley said, refusing comment on the Post's report.

Preparations also were being made for Monday's memorial service. President Bush, who ordered flags flown at half staff until sunset Tuesday, will attend.

Forensic experts, meanwhile, continued identifying the remains flown to Dover Air Force Base in flag-draped coffins. The first four bodies were to be shipped to their hometowns Saturday night.