The US has issued a worldwide travel alert because of an unspecified al-Qaeda threat.
The US state department released a statement and said the potential for an attack is partcularly strong in the Middle East and North Africa.
The BBC said the announcement has come soon after the US announced the closure of embassies in Israel, Egypt, Turkey, Algeria, Yemen, Saudi Arabia and Bangladesh on Sunday.
The travel alert which advises US citizens to be vigilant expires on August 31.
The statement said: “Current information suggests al-Qa’ida 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.”
A senior US official told NBC the threat may be related to the Islamic holy month of Ramadan.