WASHINGTON — The United States intercepted electronic communications this week among senior operatives of Al Qaeda, in which the terrorists discussed attacks against US interests in the Middle East and North Africa, US officials said Friday.
The intercepts and a subsequent analysis of them by US intelligence agencies prompted the United States to issue an unusual global travel alert to US citizens on Friday, warning of the potential for terrorist attacks by operatives of Al Qaeda and their associates from Sunday through the end of August.
The bulletin to travelers and expatriates, issued by the State Department, came less than a day after the department announced it was closing nearly two dozen US diplomatic missions in the Middle East and North Africa, including facilities in Egypt, Iraq, Yemen, Kuwait, and Saudi Arabia. Britain said Friday that it would close its embassy in Yemen on Monday and Tuesday because of "increased security concerns."
It is unusual for the United States to come across discussions among senior Al Qaeda operatives about operational planning — through informants, intercepted emails, or eavesdropping on cellphone calls. So when the high-level intercepts were collected and analyzed this week, senior officials at the CIA, State Department, and White House immediately seized on their significance. Members of Congress have been provided classified briefings on the matter, officials said Friday.
"This was a lot more than the usual chatter," said one senior US official who had been briefed on the information but would not provide details.
Spokesmen at the State Department and the CIA also declined to comment on the intercepts.
The importance of the intercepts was underscored by a speech that Al Qaeda leader Ayman al-Zawahri posted on jihadist forums Tuesday. In his address, Zawahri called for attacks on US interests in response to its military actions in the Muslim world and US drone strikes in Pakistan and Yemen, according to the SITE Intelligence Group, which monitors statements by jihadists.
Security analysts said Friday that, in the aftermath of the furor over the Obama administration's handling of the attack last year on the diplomatic mission in Benghazi, Libya, the State Department was now more likely to publicize threat warnings when deemed credible, both to alert the public and to help deter any imminent attacks.
"A decision to close this many embassies and issue a global travel warning for a month suggests the threat is real, advanced, and imminent but the intelligence is incomplete on where," said Bruce Riedel, a former CIA case officer and a Brookings Institution scholar.
The embassy closures come toward the end of the Ramadan holidays and the approaching anniversary of the Sept. 11 terror attack on the US diplomatic compound in Benghazi that killed four Americans, including Ambassador J. Christopher Stevens.
"We are particularly concerned about the security situation in the final days of Ramadan and into Eid," the British Foreign Office said in a statement, referring to the Muslim holy month that ends Wednesday evening.
Obama administration officials publicly declined to discuss what specific information had prompted the increased alarm and alerts, citing a desire to protect classified sources and methods. But intercepting electronic communications is one of the National Security Administration's main jobs.
The bulletin by the State Department's Bureau of Consular Affairs did not advise against travel to any particular country, but it warned US citizens to be particularly mindful of their surroundings, especially in tourist areas, and recommended they register their travel plans with the State Department.
"Terrorists may elect to use a variety of means and weapons and target both official and private interests," the bulletin said. "US citizens are reminded of the potential for terrorists to attack public transportation systems and other tourist infrastructure. Terrorists have targeted and attacked subway and rail systems, as well as aviation and maritime services."
Representative Ed Royce, a California Republican and the chairman of the House Foreign Affairs Committee, said Friday that the warning was linked to an Al Qaeda threat focused on the Middle East and Central Asia.
To date, the only Al Qaeda affiliate that has shown a desire and ability to attack US facilities overseas is Al Qaeda in the Arabian Peninsula, a group based in Yemen.
The Al Qaeda affiliate announced in July that its second-in-command, Saeed al-Shihri, a former Guantánamo Bay prisoner, had died as a result of injuries sustained in a US missile strike in Yemen last year. But Ibrahim Hassan al-Asiri, the group's seminal bomb maker, remains at large, and, according to US officials, has trained a cadre of skilled protégés ready to take his place should he be killed.