U.S. embassies in the Gulf were open for business as usual on Sunday, although witnesses said security was tight after Washington warned of an increased threat of “terrorist” action by Islamic militant groups.
American citizens in Saudi Arabia and Kuwait said they had received written cautions from the U.S. Department of State urging them to be vigilant and to keep a low profile.
There are around 30,000 U.S. citizens in Saudi Arabia, according to the U.S. embassy, and a further 13,000 in Kuwait.
The same warning was posted on pre-recorded phone lines in several Gulf Arab states.
The U.S. embassy in Bahrain re-opened to the public after having closed on Saturday, usually a working day in the Muslim country. Embassies in Qatar, Oman, Saudi Arabia and the United Arab Emirates were open as normal.
Witnesses in Saudi Arabia and Kuwait said security around American interests, already tight, appeared to be little changed or slightly upgraded.
A security alert has been in place in the region since May.
On Friday, U.S. officials said forces in the Gulf had been put on highest alert, Threat Condition Delta, based on a non-specific but credible threat linked to exiled Saudi dissident Osama bin Laden.
U.S. warships in Bahrain, headquarters of the U.S. 5th fleet, were ordered to sea. On Saturday, three U.S. amphibious vessels left the Red Sea port of Aqaba, cutting short a military exercise in Jordan.
Commander Jeff Gradeck, spokesman for the U.S. Navy in Bahrain, declined to comment on Sunday on where the vessels were headed.
Arabic satellite television channel MBC reported on Saturday that bin Laden’s followers were planning a major attack on U.S. and Israeli interests in the next two weeks.
U.S. network NBC has reported at least three threats of attacks on U.S. forces in the Gulf on Monday June 25, the fifth anniversary of the Khobar bombing in eastern Saudi Arabia which killed 19 U.S. servicemen.
Fourteen people have been indicted for the bombing in the U.S., though Saudi Arabia has said it will proceed with its own trial regardless.