Saudi authorities have foiled plans by suspected terrorists to carry out attacks in the kingdom and seized a large cache of weapons and explosives, the Interior Ministry said Wednesday.

Security forces seized the weapons Tuesday in the capital, Riyadh (search), as they were searching for suspects, an unidentified ministry official said.

The official, quoted by the state-run Saudi Press Agency (search), said at least 19 men -- 17 Saudis, an Iraqi holding Kuwaiti and Canadian citizenships and a Yemeni -- were being sought.

He said others also were being sought and their identities would be announced at the appropriate time.

He said some of the men opened fire on security forces pursuing them.

The suspects carjacked a vehicle after their car was damaged in a gunfight with police and then fled into a densely populated area.

The official did not disclose what the men were targeting in their terror plans. Their names and pictures were shown on state-run Saudi television; the Interior Ministry official appealed to the public to help in apprehending them and warned against giving them shelter.

The weapons and explosives confiscated from the damaged car and an apartment where some of the men were staying included hand grenades, five suitcases of high explosives weighing more than 830 pounds and AK-47 (search) rifles, authorities said. Computers, communications equipment, travel documents, cash in U.S. dollars and Saudi riyals and various items used for disguise also were seized.

The Interior Ministry announcement came six days after an American civilian working for the Saudi Royal Naval forces was attacked and slightly injured in eastern Saudi Arabia. The State Department advised Americans that day to avoid travel to Saudi Arabia because of increased terrorism concerns.

The U.S. Embassy said it had "received information that terrorist groups may be in the final phases of planning terrorist attacks on American interests in Saudi Arabia."

Interior Minister Prince Nayef said at the time that the kingdom had no information on possible attacks.

Last week, Defense Secretary Donald Rumsfeld announced that most of the 5,000 U.S. troops in Saudi Arabia would leave by the end of the summer. The presence of U.S. troops has been a major irritant to the kingdom's rulers, who face strong anti-American sentiment from the population.

American military presence in Saudi Arabia, birthplace of Islam, was among the reasons given by Usama bin Laden, the Saudi-born fugitive who heads the Al Qaeda terror network, for his hatred of the United States. He used it often as his rallying call for Muslims to attack U.S. interests worldwide.

Al Qaeda is blamed for the Sept. 11 attacks, and 15 of the 19 hijackers were Saudis. In 1996, a truck bombing killed 19 Americans at the Khobar Towers barracks in Dhahran.