WASHINGTON (AP) _ In response to a terrorist threat, a Marine Corps contingent in Jordan cut short its training session and returned to its ships, while the U.S. 5th Fleet sent its ships out of port in Bahrain.
U.S. military forces throughout the Persian Gulf were put on a heightened state of alert Friday as a precaution, although the threat picked up by U.S. intelligence agencies was not specific about an intended target, according to U.S. officials who discussed the matter on condition they not be identified.
One official said the threat was against Americans but not necessarily the U.S. military. Another official said the intelligence warning suggested that a terrorist attack was imminent.
The State Department issued a ``worldwide caution'' urging U.S. citizens to maintain a high level of vigilance abroad. It said the U.S. government has learned that American citizens and interests abroad may be at risk of a terrorist attack from extremist groups.
The statement was issued a day after 13 Saudis and one Lebanese were indicted by a U.S. grand jury in the Khobar Towers bombing in Saudi Arabia in 1996. Nineteen U.S. Air Force members were killed in the attack. Monday is the fifth anniversary of the blast.
In its announcement Friday, the State Department noted that it had said in an alert issued last month that American citizens may be the target of a terrorist threat from extremist groups with links to suspected terrorist Osama bin Laden and his Al-Qaida organization.
The statement noted that in the past, bin Laden and his allies have not distinguished between official and civilian targets.
``U.S. government facilities worldwide remain at a heightened state of alert,'' it said.
In response to the latest terrorist threat, several Navy minesweeping ships were ordered out of port in Bahrain, headquarters for the U.S. 5th Fleet that patrols the Persian Gulf area. The aircraft carrier Constellation and its battle group were already at sea, officials said.
Other security measures also were taken, but the officials would not disclose details.
The level of security _ known as the ``threatcon,'' for threat condition _ for U.S. forces in the Middle East was raised a notch, the officials said.
A contingent of Marines operating as an Amphibious Ready Group cut short its training in Jordan, the officials said. The members of the 11th Marine Expeditionary Unit from Camp Pendleton, Calif., were being taken back aboard their three vessels, led by the USS Boxer, an amphibious assault ship.
Jordanian officials confirmed that a joint military exercise with U.S. Marines was suspended indefinitely.
Some U.S. Marines left Jordan over the past few days and the rest were expected to depart Saturday, Western officials said on condition of anonymity. U.S. officials haven't said how many Marines were participating in the war games, but a Jordanian official put the number of Americans involved at about 800.
The Incirlik air station in southern Turkey, base for the American and British jets that patrol the no-fly zone over northern Iraq, has been on a heightened state of alert since Friday, said Capt. John Haynes, a spokesman there.
In Bahrain, Cmdr. Jeff Gradeck, spokesman for the U.S. Navy's 5th Fleet, refused to comment on the security situation. U.S. Embassy officials in Kuwait also would not comment on how the heightened alert in the region was affecting American troops in the emirate.
Extra security precautions for U.S. forces in the Middle East have been ordered several times since the bombing of the USS Cole in Yemen last October.