ABU DHABI ø Al Qaida launched a massive attack on Saudi Arabia's oil sector, killing as many as 17, including foreign hostages. All hostages were released early Sunday by Saudi commandos but there were an unconfirmed number of fatalities.

Al Qaida insurgents, wearing military uniforms and employing military vehicles, attacked a range of housing compounds and facilities in the kingdom's oil region near the Persian Gulf on Saturday. Saudi security sources said Western oil companies were targeted in an attack that began around 7:30 a.m. local time.

At least 17 people ø most of them Saudi guards ø were killed by Al Qaida, the sources said. Al Qaida was also said to have taken up to 50 hostages.

Early Sunday, Saudi commandos freed all hostages, but officials confirmed there had been several deaths including at least one American. Saudi security sources said four Al Qaida insurgents held the hostages at the Oasis and Ram compounds near Khobar, about 400 kilometers northeast of Riyad, Middle East Newsline reported.

"The heroic holy warriors in the Jerusalem Squad managed, by the grace of God, to raid on Saturday morning the locations of U.S. companies that specialize in oil exploration activities that have plundered the resources of Muslims," the Al Qaida Organization in the Arabian Peninsula said in a statement. "They have so far managed to kill or injure a number of crusaders, God's enemies."

The sources said most of the hostages were Western nationals, including Americans. The sources said Al Qaida gunmen had separated Muslims from non-Muslims and released five Lebanese and three Dutch nationals.

Saudi security forces tried several times to penetrate the compounds in efforts to free the hostages, the sources said.

"They [Al Qaida insurgents] were besieged by security forces in a building," a Saudi Interior Ministry statement said. "They are being dealt with in accordance with the requirements of the situation."

The casualties were said to have comprised nine Saudi guards as well as seven foreigners, including an Egyptian, Briton and U.S. national. At one point, Al Qaida operatives tied a British national to a vehicle and dragged him for two kilometers until his body was dumped near a bridge. In another attack, Al Qaida shot and killed an Egyptian schoolboy.

Al Qaida used vehicles with military insignias during their attack, the sources said. They said the insurgents drove one of the vehicles into the Arab Petroleum Investment Corp. and later stormed the Al Khobar Petroleum Center. The center contains the offices of Saudi Aramco, Royal Dutch/Shell Group, China Petroleum & Chemical Corp, France's Total and Russia's Lukoil.

"These terrorists have no respect for human life and no regard for the principles of Islam," Saudi ambassador to Washington Prince Bandar Bin Sultan said in a statement.

This was the second attack on a Saudi oil facility and the third on Westerners in May. On May 1, six Western engineers were killed when Al Qaida gunmen entered the petrochemical and refinery complex in Yanbu. The U.S. embassy in Riyad has urged Americans to leave Saudi Arabia.

The latest Al Qaida strike came amid assurances by the kingdom's oil sector that Westerners were being protected. Saudi Aramco chief executive officer Abdullah Juma told a conference in London on May 26 that the kingdom has deployed thousands of guards as well as the military to protect oil facilities and their employees.

"Our company has 5,000 security guards to protect oil facilities, in addition to the state security forces deployed around them," Jumah told the Royal Institute of International Affairs. "Land, marine and border forces are involved in the security operation to prevent terrorists and saboteurs from reaching oil facilities on land and sea. We have a huge security organization in the kingdom."