The United States issued a global travel alert Friday, citing an al-Qaida threat that also caused the State Department to close 21 embassies and consulates this weekend in the Muslim world.

The State Department warned American citizens of the potential for terrorism particularly in the Middle East and North Africa, with a possible attack occurring or coming from the Arabian Peninsula.

“Current information suggests that al-Qaida and affiliated organizations 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 statement said.

It urged American travellers to take extra precautions when travelling overseas and suggested they sign up for State Department alerts and register with U.S. consulates in the countries they are visiting.