The US State Department issued a new worldwide travel alert yesterday warning citizens of potential terror attacks originating in the Middle East and North Africa by al-Qaeda and its affiliates.
"Current information suggests that al-Qaeda and affiliated organisations continue to plan terrorist attacks both in the region and beyond, and that they may focus efforts to conduct attacks in the period between now and the end of August," the department said.
The attacks are seen as occurring in or emanating from the Arabian peninsula, according to the statement, and "may involve public transportation systems and other tourist infrastructure".
"US citizens should take every precaution to be aware of their surroundings and to adopt appropriate safety measures to protect themselves when travelling," the department said.
It recommended that Americans travelling overseas register with consular authorities on a travel registration website. The alert expires on August 31.
In Brussels, the European Union said it was also taking all needed precautions. "We are aware of the move by the US and we are in contact with our US counterparts," European Commission spokesman Alexandre Polack said. "Delegations of the EU in the affected region are liaising with US embassies."
On Thursday, the department said that several US embassies and other facilities would be closed this weekend as a "precautionary" step. More than 20 embassies and other facilities will be shut in the Middle East, North Africa and South Asia.
Spokeswoman Marie Harf said: "The Department of State has instructed certain US embassies and consulates to remain closed or to suspend operations on Sunday."
Harf did not say which facilities would be shut. A State Department official said later that the order affects embassies and consulates normally open on Sundays. It includes facilities in predominantly Muslim countries and also in Israel, where working weeks include Sundays.
An official in another US agency said there was always a chance that the information on the planned attacks was intentionally misleading in an attempt to divert attention and security from the location, timing or nature of an actual plot.
"It's my understanding that it is al Qaeda-linked, all right, and the threat emanates in the Middle East and in Central Asia," Ed Royce, the Republican chairman of the House Foreign Affairs Committee, said on CNN's New Day programme.
Additional reporting by Associated Press