US military spokesman Maj. Gen William Caldwell

The U.S. military in Iraq says coalition forces have recovered the bodies of two American soldiers missing since an attack on their checkpoint Friday.

A statement Tuesday said the soldiers' remains were surrounded by explosives when they were found Monday night near Yusufiyah, south of Baghdad.

The military says the bodies are being flown to the U.S. for positive identification through DNA testing. A military spokesman, Major General William Caldwell, said the cause of death has not been determined.

Iraqi military officials say the bodies showed signs of "barbaric" torture.

On an Islamic Web site, an Iraqi insurgent group linked to al-Qaida - the Mujahideen Shura Council claimed responsibility for the killings and said the soldiers were "slaughtered." The group also said the new leader of al-Qaida in Iraq, Abu Hamza al-Muhajer, also known as Abu Ayyub al-Masri, slit the throats of the two soldiers.

The statement could not be authenticated.

The White House national security advisor Stephen Hadley said the discovery of the bodies is a reminder that coalition forces are facing a brutal enemy that does not follow international rules of warfare.

Meanwhile, the U.S. military says coalition forces killed 15 terrorists in raids north of Baqubah. A separate statement says a senior member of al-Qaida in Iraq was detained in raids southwest of Baqubah.

General Caldwell said American troops also killed a senior member of al-Qaida in Iraq, Mansur al-Mashhadani. He said Mashhadani died Friday in a U.S. airstrike not far from where the two American soldiers disappeared.

General Caldwell said Mashhadani was a right-hand man of former al-Qaida in Iraq leader Abu Musab al-Zarqawi.