All but one of the US diplomatic posts closed this week in a sweeping response to fears of a possible al Qaeda attack will reopen on Sunday, CNN reported, citing the State Department.

The Obama administration closed 19 embassies and consulates throughout the Middle East and North Africa, and issued a worldwide travel alert due to the threat apparently linked to communications between leaders of the terror group.

The closures took effect on Sunday.

The embassy in Sanaa Yemen, where al Qaeda in the Arabian Peninsula in based, will remain closed due to continued concerns about a possible attack.

Separately, the State Department withdrew most of its diplomatic personnel from its consulate in Lahore, Pakistan, on Thursday, citing a "separate credible threat" and warned US citizens against travel to Pakistan.

Diplomatic personnel were moved to the capital, Islamabad. The Lahore facility also will remain closed.

"We will continue to evaluate the threats to Sanaa and Lahore and make subsequent decisions about the reopening of those facilities based on that information," State Department spokeswoman Jen Psaki said in a statement.

"We will also continue to evaluate information about these and all of our posts and to take appropriate steps to best protect the safety of our personnel, American citizens traveling overseas, and visitors to our facilities," she added.

One US official said there was no link between the broader terror threat and the reason for the action taken in Lahore. However, the official said it doesn't rule out a possible link to al Qaeda.

Most of al Qaeda's core leadership is believed to reside in Pakistan and Lahore known to be home to other extremists sympathetic to the group.