US hostage Paul Marshall (Xinhua/AFP)

An Islamist website on Friday showed three pictures of US engineer Paul Johnson who was kidnapped last week by al-Qaida militants in Saudi Arabia beheaded.

"To carry out our promise, the mujahedeen killed the US hostage Paul Marshall after the deadline given to the tyrannical Saudi government passed," said a statement posted on the website and signed by the Organization of al-Qaida in the Arabian Peninsula.

One of the three photos showed a man's head being held by a hand. The other two showed a beheaded body in an orange uniform lying on a bed, with the severed head placed on the back of the body.

Johnson, a 49-year-old chief engineer working for top US defense contractor Lockheed Martin, had been missing in Saudi Arabia since Saturday.

The Organization of al-Qaida in the Arabian Peninsula posted a statement on a website on Tuesday, threatening to kill Johnson unless its militants jailed in Saudi Arabia were released within 72 hours.

June 18 is the deadline set by the terrorist group for the Saudi government to satisfy its demand.

Saudi Arabia has killed or arrested dozens of terror suspects in its crackdown on al-Qaida, which has claimed responsibility for a series of deadly attacks targeting Westerners in the kingdom.

(Xinhua News Agency June 19, 2004)