Top U.S. officials are reviewing the threat of a terrorist attack that has led to the weekend closure of 21 U.S. embassies and consulates in the Muslim world and a global travel warning to Americans, according to the Associated Press.

The White House said on Saturday that President Barack Obama has been briefed on the threat and preparedness measures.

Obama’s national security adviser, Susan Rice, led the meeting and then helped brief the president, reported AP.

Among those at the meeting Saturday afternoon were the secretaries of state, defense and homeland security and the directors of the FBI and CIA.

On Friday, the United States issued a worldwide alert, warning of plans by Al-Qaeda to launch an attack in the Middle East or North Africa in August.

The State Department issued the caution to U.S. citizens a day after announcing that some two dozen embassies or consulates would be closed on Sunday as a precaution.

The State Department said attacks were possible “particularly in the Middle East and North Africa, and possibly occurring in or emanating from the Arabian Peninsula.”

“Current information suggests that Al-Qaeda 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 State Department said in a worldwide travel alert for U.S. citizens.

In an interview with ABC News, the chairman of the Joint Chiefs of Staff, Gen. Martin Dempsey, said that officials have determined there is “a significant threat stream” and that the intent is to attack U.S. and Western interests.