Jiddah, Saudi Arabia ? Saudi Arabia announced its first al-Qaida-related arrests since Sept. 11 and said Tuesday it was holding 11 Saudis, an Iraqi and a Sudanese man behind a plot to shoot down a U.S. military plane taking off from a Saudi air base.

Meanwhile, U.S. officials announced another Saudi, described as an al-Qaida operative, was in custody in Morocco. They said Abu Zubair al-Haili helped evacuate al-Qaida members from Afghanistan after Sept. 11, officials said.

The arrests in Saudi Arabia were made public through the official Saudi Press Agency, which linked the suspects to Osama bin Laden’s terror network and said they were planning to use explosives and missiles in other attacks in the kingdom.

The agency provided only sketchy details on when or where the suspects were arrested. But it was the first time since the terrorist attacks on the United States carried out by 15 Saudis and four other Arabs that the U.S. ally has announced arrests linked to bin Laden, the Saudi exile whose first cause was the overthrow of this Muslim kingdom.

The alleged plotters “were planning to carry out terrorist attacks against vital and important installations in the kingdom, by using explosives and two (surface-to-air) SA-7 missiles, smuggled into the kingdom and hidden in different places around the country,” the agency said.

Among those in custody was a Sudanese man identified by U.S. officials as Abu Huzifa, a suspected al-Qaida cell leader who has acknowledged shooting an SA-7 missile at an American plane taking off from the Prince Sultan Air Base.

The base, south of the Saudi capital of Riyadh, is home to some 4,500 U.S. troops and several military aircraft. It is being used in the war on terrorism as a command and control facility although Saudi Arabia has apparently barred the United States from stationing fighter bombers on its territory.

Saudi Arabia first invited troops to the country during the 1991 Gulf War to help defend the oil-rich nation against Saddam Hussein’s forces.

The presence of American troops in Saudi Arabia home to Islam’s holiest sites is one of bin Laden’s stated reasons for his holy war on America.