Private security men stand guard at the entrance of a road leading to the U.S consulate in Lahore on Friday. It will remain closed. (MOHSIN RAZA/REUTERS)

The State Department said that on Sunday it will reopen 18 of the 19 U.S. embassies and consulates in the Middle East and Africa that were closed last week because of terrorist threats.

It said Friday that the embassy in Sanaa, Yemen, would remain closed “because of ongoing concerns about a threat stream indicating the potential for terrorist attacks emanating from Al Qaeda in the Arabian Peninsula.” Americans in Yemen were advised to leave the country Tuesday, and many embassy officials were evacuated after intercepted al-Qaeda communications indicated an attack was being planned.

The U.S. consulate in Lahore, Pakistan, where the closure was announced Thursday based on “a separate credible threat,” will remained closed, the statement said.

“We will continue to evaluate the threats to Sanaa and Lahore and make subsequent decisions about the reopening of those facilities,” the statement said.

A worldwide travel alert warning U.S. citizens of potential terrorist attacks, put into effect Aug. 2, remains in effect until at least the end of this month.