WASHINGTON — U.S. and European embassies in the Middle East and North Africa were to be closed Sunday after the United States intercepted communications between high-ranking al-Qaida terrorists.

U.S. National Security Adviser Susan Rice led a meeting at the White House Saturday to discuss the threat with Secretary of State John Kerry, Defense Secretary Chuck Hagel, Secretary of Homeland Security Janet Napolitano, the heads of the FBI and CIA, and other military and intelligence advisers.

President Barack Obama did not attend the meeting, but has been receiving frequent briefings since instructing "his National Security team to take all appropriate steps to protect the American people in light of a potential threat occurring in or emanating from the Arabian Peninsula," the White House said.

The New York Times quoted U.S. officials as saying that communication was intercepted between senior al-Qaida members discussing plans for operations in the region.

"This was a lot more than the usual chatter," an official said.

France joined Germany and Britain in closing its embassy in Yemen on Sunday, after the U.S. said 21 diplomatic posts would be closed. French President Francois Hollande called on French citizens in Yemen to exercise caution.

Interpol issued a global security alert for increased vigilance amid a series of prison escapes in Iraq, Libya and Pakistan.

It "suspected al-Qaida involvement in several of the breakouts which led to the escape of hundreds of terrorists and other criminals."

Al-Qaida leader Ayman al-Zawahiri had called earlier this week for attacks on U.S. interests.

In a separate message released Saturday, al-Zawahiri accused the U.S. of "plotting" with the Egyptian army to oust Islamist president Mohammed Morsi last month.

The U.S. government on Friday issued a worldwide travel alert over terrorist threats and moved to close down 21 diplomatic posts in 17 countries from Algeria to Bangladesh.

Britain and Germany planned to close diplomatic offices in Yemen as London warned its citizens to leave the country. The British and German embassies are to be shuttered on Sunday and Monday.

Washington warned its citizens of "continued potential" for al-Qaida and allied groups to mount attacks. The main threat emanated from the Arabian Peninsula, the State Department said.

Germany's diplomatic outposts in Yemen were to remain closed on Sunday and Monday out of security concerns, a spokesman for the Foreign Ministry in Berlin said.

A spokeswoman in the British Foreign Office said its embassy in the Yemen capital of Sana'a would also be closed on the two days as a "precautionary measure."

The U.S. closures include Sana'a, Cairo, Kabul, Tripoli, Algiers, Amman, Djibouti, Dhaka, Doha, Khartoum, Kuwait City, Manama, Muscat and Nouakchott.

It will also close offices in the Saudi cities of Riyadh, Jeddah and Dhahran; in Baghdad and Erbil, Iraq; and in the United Arab Emirates of Abu Dhabi and Dubai.

"There's very little doubt it's something serious," U.S. Rep. Peter King, chairman of the House subcommittee on counterterrorism and intelligence, told CNN. "This has been developing for awhile."

Experts said the escalating terrorist danger accompanies the end of the Muslim holy month of Ramadan.

The U.S. travel alert through August includes the end of Ramadan and the run-up to the Sept. 11 anniversary of al-Qaida's airplane attacks against New York and Washington.

Clashes in Sana'a were reported Friday by Britain's Press Association, which said a group of soldiers had joined a mutiny that tried to storm the presidential palace. One of the mutineers was killed, and tanks and armored vehicles were deployed to protect the palace.

Earlier in the week, two separate U.S. drone strikes killed seven militants in Yemen with suspected links to al-Qaida. The attacks came just ahead of Yemeni President Abdo Rabu Mansour Hadi's meeting with Obama at the White House on Thursday.

The State Department said al-Qaida and affiliated organizations "continue to plan terrorist attacks both in the region and beyond" through to the end of August.

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