KUWAIT - Kuwait and its main ally the United States appeared Monday to be at odds once again over a new shooting incident involving U.S. soldiers.

The U.S. Embassy in Kuwait said American troops training in the desert were shot at from two vehicles but several Kuwaiti officials said it was probably a group of bird shooters who fired in the air and alarmed the soldiers.

The some 10,000 American forces here have been on heightened alert after two Kuwaitis attacked U.S. Marines while training on a Kuwaiti island last Tuesday, killing one and wounding another.

Kuwait said last week's attack was a "terrorist act" but, so far, it has not issued an official government statement on Monday's incident. No arrests have been made following the latest incident, sources said.

A non-American Western defense source in Kuwait said Monday's shooting "appears to us to be bird shooters."

A senior Kuwait official, casting doubts on the U.S. version, told Reuters "this is the bird migration season through Kuwait and many people go to the desert ... terrorists would not fire in the air and then go."

But the U.S. embassy reiterated in a statement:

"Shots were fired from the occupants of two unidentified civilian sports utility vehicles at United States military units near a northern Kuwaiti training area" at 7:50 a.m.

It said there were no injuries in Monday's incident and that the ground forces, taking part in the Desert Spring training exercise, did not fire back.

The speaker of Kuwait's elected parliament Jassem al- Kharafi, adding to Kuwaiti doubts, told Reuters by telephone: "It has not been confirmed yet what the shooting was. It could have been bird hunting, it is still not clear."

ODDS AT CRITICAL TIME

It was the third shooting incident in a week. Last Wednesday, a U.S. soldier fired a single bullet at a car in northern Kuwait, apparently sensing a threat as troops traveled on a highway. No one was injured.

The incidents come at a critical time when the United States appears to be preparing for a possible war against Kuwait's former occupier Iraq, pouring additional military hardware into Kuwait and the region over recent months.

Cooperation and liaison between the two sides appeared to breakdown last Tuesday for a few hours when the two Kuwaitis in a white pick-up truck attacked the Marines. The two men, who trained in al Qaeda camps, were killed in a shootout with the Marines.

A joint U.S.-American probe, which includes FBI agents who arrived Sunday, was launched to investigate the incident and clear differences over jurisdiction and other matters which emerged after the shooting.

Kuwait Interior Minister Sheikh Mohammad Khaled al-Sabah told a news conference that confusion reigned for a few hours after Tuesday's attack which was followed by the arrest of a cell that plotted the hit and had plans for more targets.

But Kuwait said it had not established a direct link between the cell and Osama bin Laden's al Qaeda group.

The world's most wanted man Monday allegedly praised the perpetrators of the Marines attack and an October 6 blast which gutted the French-flagged tanker Limburg off Yemen.

He warned the United States and Israel in a statement of more carnage to come.

Meanwhile, the French embassy in Kuwait advised its some 800-strong community to exercise "the greatest prudence" when moving outside Kuwait City and to avoid traditional markets.

Kuwait has set up new road checkpoints and security around embassies and schools has been stepped up in recent days.

The United States, which played a leading role in the 1991 Gulf War that drove out Iraqi troops, has about 8,000 civilians in Kuwait.