A meeting of the National Security Council chaired by Susan Rice was held at the White House Saturday evening to discuss the latest intelligence regarding the threat of an al Qaeda attack.
There are different views among analysts -- including whether a plot is already underway, with team members already selected, as reported Saturday by CBS.
At least some present at the meeting said they believed that to be the case, but others disagree. There is no consensus on whether the plot is underway, officials told NBC News.
The threat of an al Qaeda attack is “real and serious” and “we must not let our guard down,” the chairman of the House Permanent Select Committee on Intelligence warned after a worldwide alert was issued for all U.S. citizens traveling abroad.
In a statement issued Friday, the State Department warned the terror group and its affiliates “may focus efforts to conduct attacks in the period between now and the end of August.”
On Saturday, President Obama was updated on a potential threat coming from the Arabian Peninsula, a White House official said. The president would continue to be updated throughout the weekend, according to the official.
U.S. officials said that the threat warning is based primarily on a "significant increase in chatter from a growing number of intercepts" throughout the region.
Mike Rogers, the intelligence committee chairman, said the situation showed just how dangerous the al Qaeda network still is.
“The seriousness of the threat stream is a sober reminder of al Qaeda's determination and ongoing intention to commit acts of violence on Western and U.S. targets,” he said in a statement late Friday.
“The threats against American interests are real and serious and we must not let our guard down,” he added.
At least 22 embassies and consulates that normally open on Sundays -- mostly in the Muslim world -- were closing this weekend because of the potential threat.
The closures so far include diplomatic missions in Cairo, Tel Aviv, Riyadh, Baghdad, Kabul, and Bahrain.
"It is possible we may have additional days of closings as well, depending on our analysis,” a State Department official said.
The chairman of the House of Representatives Foreign Affairs Committee, Ed Royce, told MSNBC he believed it was “probably now prudent, given the fact that, in this case, we do have this intelligence, to take this step to make certain that we have fully protected our embassy personnel.”
Britain said it would close its embassy in Yemen on Sunday and Monday. "We are particularly concerned about the security situation in the final days of Ramadan and into Eid," Britain's Foreign Office said in a statement, referring to the Muslim holy month that ends on Wednesday.
The intelligence says nothing about a specific target of the plot, U.S. officials said Friday. The United States is working with foreign spy agencies to try to find out more about the target.
The State Department’s alert said U.S. citizens “should take every precaution to be aware of their surroundings and to adopt appropriate safety measures to protect themselves when traveling.”
"The Department of State alerts U.S. citizens to the continued potential for terrorist attacks, particularly in the Middle East and North Africa, and possibly occurring in or emanating from the Arabian Peninsula,” it added.
Terrorism expert Xenia Dormandy, U.S. director of London-based think tank Chatham House, said Friday it was the first time in memory that the U.S. had closed such a large number of embassies at once.
“The bottom line is clearly they’ve had firm intelligence from multiple sources that there’s an al Qaeda threat or an al Qaeda-affiliated threat," she said.
Dormandy said the United States' actions were likely influenced by the attack on the U.S. Consulate in Benghazi, Libya, in September, in which Ambassador Christopher Stevens and three other Americans were killed.
“I think they are being cautious because any attack on American diplomats is something they want to avoid at all costs," she added. "I think they are certainly likely to be more nervous now about making a mistake than they were before the Libyan [Benghazi consulate] attack, but they’ve seen the consequences of what can happen if you don’t take precautions, so it’s perhaps an appropriate response."
Ian Johnston and Henry Austin of NBC News and Reuters contributed to this report.