DUBAI, June 18: Al Qaeda militants beheaded an American engineer they had held hostage since last week after the Saudi government failed to meet its demands to release jailed militants, an Islamist website said on Friday.

"As we promised the mujahideen, we have beheaded the American hostage Paul Marshall after the deadline that the mujahideen gave to the tyrannical Saudi government passed," a statement signed by the Organisation of al Qaeda in the Arabian Peninsula said on Al Islah website.

The website showed three pictures of what appeared to be Paul Marshall Johnson's severed head. One showed the bloodied head propped up on the back of a body in an orange uniform with a knife on the face.

A second picture showed a hand lifting up the head and a third image showed the body and the severed head from a different angle. "This act of revenge is to heal the hearts of believers in Palestine, Afghanistan, Iraq and the Arabian peninsula," the statement said.

"This is God's voice rising in anger... at the treatment of Muslims in Abu Ghraib, al-Hair (prison), Guantanamo, Ruwais (Saudi prison) and others," it added, referring to US military prisons in Abu Ghraib, Iraq and Guantanamo Bay, Cuba. The body of Paul Marshall Johnson was found in the Saudi capital Riyadh, a Saudi web news site said late Friday night. -Reuters