Thursday, October 10, 2002 Posted: 10:09 PM EDT (0209 GMT)

WASHINGTON (CNN) -- With al Qaeda "chatter" on the rise, senior U.S. officials are increasingly concerned about possible terrorist attacks against U.S. interests, including an alleged plot targeting American schoolteachers and their schools within Kuwait.

The concern was reinforced Thursday when French and U.S. investigators reached a preliminary conclusion that Sunday's explosion aboard a French oil tanker in Yemen was the work of terrorists. One crewman was killed in the blast, which spilled thousands of gallons of oil into the sea. (Full story)

U.S. investigators said TNT residue, fiberglass and small marine engine parts were found aboard the Limburg -- appearing as if the explosion mirrored the bombing of the USS Cole in October 2000, when a bomb-laden dinghy blew a hole in the side of the ship, killing 17 U.S. sailors.

A junior officer aboard the French tanker reported a boat quickly approaching shortly before the explosion, said a spokesman for the ship's operator, France Shipmanagement.

One senior Pentagon official said a local newspaper in Yemen received a communication from an Islamic group claiming responsibility for the tanker explosion. It was not immediately known if the group has direct ties to al Qaeda.

French Foreign Ministry spokesman Francois Rivasseau said the ministry directed all French diplomatic missions in the region to take all necessary steps to avoid risk. U.S. issues 'worldwide caution'

The level of concern over a potential attack on U.S. interests has only intensified since two taped al Qaeda statements -- one purportedly from Osama bin Laden, the other possibly from his top lieutenant -- were released within the past week.

Senior U.S. officials said the two messages are "cause for concern."

U.S. intelligence officials give more credence to the tape from bin Laden's top deputy, Ayman al-Zawahiri, because he names current events, including the September 11 anniversary and potential U.S. military action against Iraq. Analysts estimated the tape was made as recently as July.

On the tape, the man believed to al-Zawahiri -- a key al Qaeda strategist who was indicted in the 1998 U.S. embassy bombings in Africa -- warns of fresh attacks against the United States, its economy and its allies. France was among the allies named as targets.

Senior-level detainees in the war against terrorism told U.S. officials the al-Zawahiri tape would never have been released if there was not already another attack planned, the officials said.

Senior officials in the U.S. intelligence community also are concerned about the current high level of "chatter" and communications between suspected al Qaeda members.

With the threats swirling, the State Department issued a new "worldwide caution" warning Americans abroad to be on alert for a possible attack by the al Qaeda terrorist network.

"The U.S. government continues to receive credible indications that extremist groups and individuals are planning additional terrorist actions against U.S. interests," the advisory read.

The FBI overnight Wednesday sent a terrorist threat advisory to law enforcement agencies nationwide telling them to "implement additional prudent steps to detect, disrupt, deter, and defend against potential attacks."

Of particular concern to counterterrorism officials are the threats associated with the al-Zawahiri tape because it cites a threat to U.S. economic interests.

"The coordinated release of these statements, coupled with our knowledge of ongoing plotting by al Qaeda members and threat information described by detainees, strengthens previous assessments that al Qaeda continues to plan major attacks against U.S. interests," the FBI advisory said. Kuwait finds diagrams, plans for attack

In another development, senior military officials said the Kuwaiti Ministry of Interior told the U.S. government it believed American schoolteachers and their schools in Kuwait are targeted for terrorist attacks as well as U.S. military and diplomatic installations.

Pentagon officials said Kuwaitis warned them the next possible attack would be a "multi-story" target. Kuwait is a tiny nation tucked between Iraq and Saudi Arabia.

An independent Kuwaiti newspaper also reported investigators uncovered diagrams and plans for an attack, possibly against an embassy facility or a school.

The new warning came days after a U.S. Marine was killed on a Kuwaiti island Tuesday and another wounded when two assailants -- believed to have ties with al Qaeda -- opened fire on Marines during a training exercise. Both shooters were killed by U.S. military police.

Kuwaiti officials said the attack may have been the "first response" to the messages on the tapes.

Since the Tuesday attack, Kuwaiti authorities have rounded up more than 200 people, including about 30 Islamic fundamentalists who admitted going to Pakistan or Afghanistan for training.

Five individuals in custody admitted to a direct role in the attack, and Kuwaiti authorities said they were searching for three or four others.

One of those under investigation is the head of Kuwait's main mosque, which essentially serves as the state mosque.

Well-placed Kuwaiti sources said Yasser al-Failakawi -- the imam of the Grand Mosque of Kuwait where politicians and royalty come to pray -- may have helped the two assailants get on the island to carry out the attack.

On Wednesday, gunmen pulled up next to a U.S. military Humvee on the Kuwaiti mainland and drew a weapon. One of the two U.S. troops in the Humvee fired a shot, forcing the assailants to swerve off the road. The U.S. forces were not injured.

Later, two occupants of the vehicle told investigators they had only a cell phone when they approached the Humvee.

Thursday, three Marines participating in a training exercise in Kuwait were wounded when a piece of ordnance exploded when they either walked or drove over it.

Pentagon officials said they believed the incident was an accident, although they were investigating. It was not immediately clear what kind of device went off.

-- Anonymous, October 10, 2002