Story highlights Bergen, Cahall: U.S. issued global travel alert, 21 embassies, consulates close Aug. 4

That day is Ramadan 'Night of Power,' also seen by al Qaeda as good night for martyrdom

They say night of power has brought earlier terror attacks; embassies a favored target

Writers: Target may be Egypt, where earlier attack aimed; jailbreaks may also be factor

On Friday the U.S. State Department issued a worldwide travel alert because of an unspecified al Qaeda threat. The location of that threat, the department said in a bulletin, is "particularly in the Middle East and North Africa, and possibly occurring in or emanating from the Arabian Peninsula." As a result, an unprecedented 22 embassies and consulates in 17 countries in the Middle East, North Africa and South Asia closed for a day on Sunday.

Sunday is also the 27th day of Ramadan and a particularly holy day for the world's Muslims as it is the "Night of Power," when the first verses of the Koran were revealed to the Prophet Mohammed.

It is also seen by al Qaeda's would-be martyrs as a particularly auspicious day to die.

On the Night of Power in 2000, which that year fell on January 3, al Qaeda militants attempted to launch a suicide attack against the American warship USS The Sullivans off the coast of Yemen with a bomb-filled boat.

That attack failed, but the same group of militants then attacked the USS Cole 10 months later, again using the tactic of a bomb-laden boat, which exploded, killing 17 American sailors.

Photos: Embassy closings Photos: Embassy closings Intercepted message spurs embassy closings – A recently intercepted message among senior al Qaeda operatives alarmed the U.S. State Department and led to the closing of 22 embassies and consulates Sunday, August 4, across the Middle East and North Africa. On Sunday afternoon, the State Department said it had extended the closures in 15 of the locations until Saturday, August 10, and added four other posts to the list. Click through to see which facilities are affected, beginning with the U.S. Embassy in Amman, Jordan, which is closed for the week. Hide Caption 1 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. embassy in Dhaka, Bangladesh, was closed August 4 but was scheduled to reopen on Monday, August 5. Hide Caption 2 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in the Saudi capital of Riyadh will be closed for the week along with the consulates in Dhahran and Jeddah. Hide Caption 3 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Muscat, Oman, will remain closed through August 10. Hide Caption 4 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Tripoli, Libya, is closed for the week. Hide Caption 5 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Kabul, Afghanistan, was closed on Sunday and reopened Monday. The consulate in the Afghan city of Mazar-e Sharif was also closed and reopened. Hide Caption 6 of 20 Photos: Embassy closings Intercepted message triggers embassy closings – The U.S. Embassy in Baghdad, Iraq, shown here under construction in October 2007, reopened August 5. The consulates in Basrah and Erbil, which were closed, also resumed normal business on Monday. Hide Caption 7 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Cairo, Egypt, shown here during a demonstration on September 11, 2012, will remain closed. Hide Caption 8 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Antananarivo, Madagascar, was one of four embassies added to the list of facilities to remain closed for the week. The others were the embassies in Burundi, Rwanda and Mauritius. Hide Caption 9 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Sanaa, Yemen, is closed until August 10. Hide Caption 10 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Doha, Qatar, is closed for the week. Hide Caption 11 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Algiers, Algeria, closed on August 4 and reopened the next day. Hide Caption 12 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – Officials announced that they would add the U.S. Embassy in Port Louis on the island of Mauritius to the list of facilities that will be closed for the week. Hide Caption 13 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S Embassy in Kigali, Rwanda, will remain closed for the week. Hide Caption 14 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Khartoum, Sudan, will remain closed for the week. Hide Caption 15 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Manama, Bahrain, will remain closed for the week. Hide Caption 16 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Nouakchott, Mauritania, reopened August 5. Hide Caption 17 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Kuwait City, Kuwait, will remain closed for the week. Hide Caption 18 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Djibouti will remain closed. Hide Caption 19 of 20 Photos: Embassy closings Intercepted message spurs embassy closings – The U.S. Embassy in Abu Dhabi, United Arab Emirates, will remain closed along with the consulate in Dubai. Hide Caption 20 of 20

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It was the day after the Night of Power in December 2001 that Osama bin Laden signed his will as he feared death from American bombs falling during the battle of Tora Bora in eastern Afghanistan.

Al Qaeda and aligned organizations have a long history of attacking U.S. embassies and consulates, beginning in 1998 with the bombings of the embassies in Tanzania and Kenya, which killed more than 200, and including, most recently, the storming of the U.S. government facility in Benghazi, Libya, on the 11th anniversary of 9/11 last year.

For al Qaeda, these diplomatic compounds are attractive targets because they symbolize American power and because their locations are widely known. Indeed, several of the embassies and consulates closed on Sunday have been attacked by al Qaeda and affiliated groups before.

In Saudi Arabia, militants breached the outer wall of the U.S. consulate in Jeddah on December 7, 2004, killing five.

The U.S. embassy in Sana'a, Yemen, was targeted by an al Qaeda affiliate two times in 2008, attacks that killed 21.

On September 13, 2011, the Haqqani network, a Taliban group closely associated with al Qaeda, attacked the U.S. Embassy in Kabul, killing five Afghan police officers and 11 civilians.

Though U.S. officials have not confirmed the targeting of a specific embassy, it is likely that the American compound in Cairo is a particular point of concern. In May, three men were arrested by Egyptian officials, who said the men were planning to attack the embassy. Officials said they discovered 22 pounds of aluminum nitrate, instructions on how to make bombs, and materials published by al Qaeda in the Islamic Maghreb, the network's North African affiliate.

Another possible factor in the timing of the al Qaeda alert is that in the past two weeks, massive jailbreaks in Iraq and Libya have released more than a thousand prisoners, some with significant ties to al Qaeda. Very few of those inmates have been recaptured.

The U.S. embassies in Baghdad, Iraq, and Tripoli, Libya, are among the facilities that will be closed on Sunday.

(Note: An earlier version of this story misstated the timing of Osama bin Laden's will signing.)