The State Department is ordering the closure of a number of U.S. embassies and consulates beginning Sunday due to a possible Al-Qaeda threat, NBC News and CNN are reporting.

All U.S. diplomatic posts across the Middle East and North Africa will close August 4 and could remain shut for an extended period, a State Department official told NBC News. At least 16 embassies and consulates are affected.

Word of the embassy closures first came Thursday, when the State Department did not specify the type of threat posed.

Officials told NBC the threat appeared related to Al-Qaeda and linked to the Muslim holy month of Ramadan, which ends Wednesday.

This post has been updated.