Story highlights The U.S. State Department extends closures of some diplomatic posts

An intercepted al Qaeda message led to the closing of embassies and consulates

CNN national security analyst: "Some of this ... is about buying time"

In Yemen's capital, some say warnings about attacks are overblown

An intercepted message among senior al Qaeda operatives in the last several days raised alarm bells that led to the closing of embassies and consulates Sunday across the Middle East and North Africa, CNN has learned.

CNN has agreed to a request from an Obama administration official not to publish or broadcast additional details because of the sensitivity of the information.

Several U.S. officials also emphasized they have been watching growing threats emerging from Yemen for weeks.

Those threats, combined with the coming end of the month of Ramadan, plus the concern over several major prison breaks in the region, all contributed to the U.S. decision to shut down diplomatic installations.

Officials shuttered 22 U.S. embassies and consulates for the day on Sunday amid fears of an al Qaeda attack. On Sunday afternoon, the State Department said it had extended embassy and consulate closures in 15 of the locations until Friday and added four other posts to the list.

"This is not an indication of a new threat stream," the State Department said, "merely an indication of our commitment to exercise caution and take appropriate steps to protect our employees, including local employees, and visitors to our facilities."

The widespread closure of diplomatic posts is an unprecedented move.

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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"We're doing what is necessary to protect our people," Rep. Adam Schiff, a Democrat on the House Intelligence Committee, told CNN's State of the Union on Sunday.

The closures stretch across a swath of Africa and the Middle East -- as far west as Mauritania, as far south as Madagascar and as far east as Oman. A U.S. global travel alert is also in place.

Interpol warned that that led to the escape of hundreds of terrorists and other criminals. As White House and national security officials met to discuss the threat and U.S. military forces in the Middle East were put on a higher state of alert,Interpol warned that al Qaeda has been tied to prison breaks in the regionthat led to the escape of hundreds of terrorists and other criminals.

It's unclear what locations are targeted by the apparent terror plot, U.S. lawmakers said Sunday.

"I think we know a lot more about the when than the where. And you can tell that from the breadth of the closures across North Africa and the Arabian Peninsula," Schiff said. "But the when was very specific in terms of a Sunday. Obviously, that may continue and the closures may continue. The travel warning is more extensive. But this is not the usual kind of chatter, not the more generalized 'death to the Americans' or 'death to great Satan.' "

CNN national security analyst Fran Fragos Townsend said there could be a strategic reason for shutting down the diplomatic offices.

"Once you take targets away, it buys you additional time to try and disrupt, to identify the cell, the operators in country and the region, and work with your partners in the region to try and, you know, get them in custody or disrupt the plot," she said. "So, some of this operationally is about buying time."

Of particular concern is Yemen, where the government is "on high alert against possible attacks in the days to come," said a senior U.S. security official.

Over the weekend, the security around the U.S. Embassy in Yemen was even tighter than last year, when protesters raided it. At least 12 tanks were stationed within 500 meters of the building.

Britain, France and Germany also closed their embassies in the Yemeni capital, Sanaa, on Sunday and Monday for security reasons. No other embassies are affected, they said.

Western targets under threat

"The threat appears to be much worse than it has (been) in a long time," said a senior U.S. security official in Yemen.

Various Western targets -- not just those tied to the United States -- are under threat, two U.S. officials said.

Three sources said the United States has information that members of al Qaeda in the Arabian Peninsula are in the final stages of planning for an unspecified attack.

One of the sources said such preparations appeared to have increased in recent days, with the approaching end of the Muslim holy month of Ramadan. Sunday is Laylet al-Qadr, or the Night of Power, one of the holiest moments on the Muslim calendar.

Said one U.S. official: "It all leads us to believe something could happen in the near future."

Rep. Michael McCaul, chairman of the House Homeland Security Committee, told CBS' "Face the Nation" Sunday that it was "one of the most specific and credible threats I've seen perhaps since 9/11."

"Because of the specificity, because of where it is coming from, the credibility of it, the level of chatter, it seems to be a fairly large operation," he said. "It's giving the intelligence community quite a bit of pause right now."

Concerns about Yemen

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Photos: Photos: Attack on U.S. mission in Benghazi Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Attackers set the U.S. mission in Benghazi, Libya, on fire on September 11, 2012. The U.S. ambassador to Libya, Christopher Stevens, and three other U.S. nationals were killed during the attack. The Obama administration initially thought the attack was carried out by an angry mob responding to a video, made in the United States, that mocked Islam and the Prophet Mohammed. But the storming of the mission was later determined to have been a terrorist attack. Hide Caption 1 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Obama and Clinton stand at Andrews Air Force Base as the bodies of the four Americans killed are returned on September 14. Hide Caption 2 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A desk sits inside the burnt U.S. mission on September 13, two days after the attack. Hide Caption 3 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Damage is seen inside the U.S. mission on September 13. Hide Caption 4 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A lounge chair and umbrella float in the swimming pool of the U.S. mission on September 13. Hide Caption 5 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Demonstrators gather in Libya on September 12 to condemn the killers and voice support for the victims. Hide Caption 6 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – U.S. President Barack Obama, with Secretary of State Hillary Clinton on September 12, makes a statement at the White House about Stevens' death. Hide Caption 7 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A burnt vehicle is seen at the U.S. mission in Benghazi on September 12. Hide Caption 8 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – People inspect the damage on September 12. Hide Caption 9 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A small American flag is seen in the rubble on September 12. Hide Caption 10 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A man stands in part of a burned-out building of the U.S. mission on September 12. Hide Caption 11 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Smoke and fire damage is evident inside a building on September 12. Hide Caption 12 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Half-burnt debris and ash cover the floor of one of the U.S. mission buildings on September 12. Hide Caption 13 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – The U.S. mission is seen in flames on September 11, the day of the attack. Hide Caption 14 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A protester reacts as the U.S. mission burns on September 11. Hide Caption 15 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A vehicle and the surrounding area are engulfed in flames on September 11. Hide Caption 16 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Flames erupt outside of a building on September 11. Hide Caption 17 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A vehicle burns during the attack on the U.S. mission on September 11. Hide Caption 18 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Onlookers record the damage from the attack on September 11. Hide Caption 19 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Onlookers walk past a burning truck and building on September 11. Hide Caption 20 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A vehicle sits smoldering in flames on September 11. Hide Caption 21 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – People duck flames outside a building on September 11. Hide Caption 22 of 22

U.S. officials said that based on intelligence, they were particularly concerned about the U.S. Embassy in Yemen between Saturday and Tuesday. President Barack Obama, amid regular updates on the situation, has directed officials to take all appropriate steps to protect Americans.

Hundreds of additional security forces were deployed, and roads leading to the embassy were closed. Checkpoints were set up at a distance from the embassy, and trucks weren't allowed to pass anywhere near the main embassy road.

Yemen's special forces, the most elite, were seen in small numbers near the embassy as well.

The UK Foreign Office has also warned its citizens against travel to Yemen, and it urged British nationals to leave as soon as possible.

"If you don't leave the country now while commercial carriers are still flying, it is extremely unlikely that the British government will be able to evacuate you or provide consular assistance," it said.

In Sanaa, some said concerns about attacks were overblown.

Wagdi Al-Absi, a university professor based there, told CNN that the threats and warnings are exaggerated.

"Al Qaeda was a real threat and very powerful in Yemen two years ago. Still, embassies did not close," he said. "Today, when al Qaeda is handicapped, the West considers them a real threat. It's the total opposite.

"Streets in Yemen are normal, and security forces are always on the watch. That is why al Qaeda attacks in the capital are not common."

Time of attack unknown

The expected time of an attack is unknown, which explains why a U.S. travel alert extends through August.

"Terrorists may elect to use a variety of means and weapons and target both official and private interests," the alert states. "U.S. citizens are reminded of the potential for terrorists to attack public transportation systems and other tourist infrastructure."

U.S. Rep. Peter King of New York, a member of the House Intelligence Committee, called the information "the most specific I've seen."

While the principal attention is on the Arabian Peninsula, he stressed to CNN's Wolf Blitzer that "we can't rule anything out."

"We are focused on the Middle East, but it's a potential series of attacks that really could be almost anyplace," King said.

U.S. forces on alert

Select U.S. military forces in the Middle East were put on a higher state of alert.

Defense Secretary Chuck Hagel held a series of high-level meetings at the Pentagon "to take a look at what forces we have in the region" that can be used if there is an attack, a U.S. official told CNN.

These forces are at "quite a high state of readiness achieved only a handful of times in the last year," the official said. He declined to be specific, but two other officials have told CNN that U.S. Navy amphibious ships in the Red Sea last week moved closer to Yemen.

There are also combat-equipped Marines in southern Spain and southern Italy that could begin moving in as little as one hour from getting orders.

The U.S. military has taken similar action in recent months, especially at times of unrest in Yemen and Egypt. These forces in the Red Sea, Spain and Italy have been regularly deployed to these areas since last year's attack in Benghazi, Libya, when the U.S. military did not have forces nearby.

Unprecedented move

Christopher Hill, a former U.S. ambassador to Iraq, told CNN he had never seen embassy closures ordered across such a broad area.

"There have been incidents where they've closed down a number of embassies in the Middle East because the information is not specific enough to say that 'embassy X' got to be closed as opposed to other embassies," said Hill, who joined the U.S. Foreign Service in 1977.

"But I think this, closing all of these embassies in the Middle East to North Africa, is in fact unprecedented. At least, I didn't see this during my career."

Concerns after Benghazi

House leaders have been briefed, Democratic leader Nancy Pelosi told reporters, adding that the travel alert and embassy closings provided "some understanding of the seriousness of the threat."

King, who has also heard such briefings, applauded the government's decision to close its diplomatic missions.

"I give them credit," the Republican said of the Obama administration. "I think the government is doing exactly the right thing here."

Such bipartisan agreement in Washington comes at a time when politicians are still scrutinizing the September 11, 2012, attack on the U.S. consular compound in Benghazi, which killed four Americans, including Ambassador Christopher Stevens.

Since then, Republicans have been pressing Obama's administration for answers, with some accusing officials of covering up what happened in Benghazi and not doing enough to track down the attackers.

Eight GOP lawmakers are asking that incoming FBI Director James Comey brief Congress within 30 days about the investigation. They say the administration's inquiry to date has been "simply unacceptable," according to a draft letter obtained by CNN.

Earlier last week, Vice President Joe Biden and senior State Department officials went to Congress to discuss embassy security.

Biden also briefed congressional leadership, key committee chairmen and ranking members about the latest threat concerns, a source who attended the meeting said.

Another official said the recent intelligence might not have warranted such a response before the Benghazi attack, which created a political firestorm for the administration.

On Thursday, State Department spokeswoman Marie Harf said the agency was taking the steps out of an abundance of caution.

List of closures

The following U.S. posts will be closed Monday to Friday:

U.S. Embassy Manama, Bahrain

U.S. Embassy Bujumbura, Burundi

U.S. Embassy Djibouti, Djibouti

U.S. Embassy Cairo, Egypt

U.S. Embassy Amman, Jordan

U.S. Embassy Kuwait City, Kuwait

U.S. Embassy Tripoli, Libya

U.S. Embassy Antananarivo, Madagascar

U.S. Embassy Port Louis, Mauritius

U.S. Embassy Muscat, Oman

U.S. Embassy Doha, Qatar

U.S. Embassy Kigali, Rwanda

U.S. Consulate Dhahran, Saudi Arabia

U.S. Consulate Jeddah, Saudi Arabia

U.S. Embassy Riyadh, Saudi Arabia

U.S. Embassy Khartoum, Sudan

U.S. Embassy Abu Dhabi, United Arab Emirates

U.S. Consulate Dubai, United Arab Emirates

U.S. Embassy Sanaa, Yemen