US forces on high alert after threat of attack

The Pentagon placed US forces in the Gulf on the highest state of alert yesterday, cutting short a joint military exercise in Jordan and ordering US Navy ships out of port in Bahrain, where the Fifth Fleet is based.

The threat was described as "non-specific", meaning that it was believed to target Americans in general rather than the military alone. But it was categorised as "credible and actionable". Ordering ships out of port has been standard procedure since the attack on the USS Cole as it was refuelling in the Yemen port of Aden nine months ago.

The alert came the day after a grand jury near Washington indicted 14 people, including 13 Saudi citizens and one Lebanese, in connection with the bombing of the Khobar Towers in Saudi Arabia in which 19 American servicemen died. The fifth anniversary of that bombing falls next week.

None of the individuals is in US custody, and the Saudi authorities said yesterday that the US had no right to take legal action against them. Responsibility for any judicial action, they said, rested with Saudi Arabia.

Pentagon sources said that intelligence intercepts had picked up a communication between two men from the region that suggested a major attack was imminent. All non-essential military air traffic in the region will be halted for as long as the alert continues, including supply flights and transports of personnel.

US forces were last put on alert in the region less than one month ago, after a New York jury convicted four people, believed to be associates of the Afghanistan-based terrorist Osama bin Laden, for the 1998 US embassy bombings in Africa.