U.S. embassies in 19 cities across the Middle East and North Africa remain on lockdown Monday and may remain so through the end of the week.
The State Department closed them after intercepted intelligence showed that high-level al Qaeda terrorists are planning a major attack. U.S. officials call the intercepted threats against Americans "serious and credible."
CBN News Terrorism Analyst Erick Stakelbeck offers his take on this latest al Qaeda threat following Efrem Graham's report.
"We've received information that high level people from al Qaeda in the Arabian Peninsula are talking about a major attack and these are people in the high level," Rep. Dutch Ruppersberger, D-Md., told ABC's "This Week."
"This threat was so specific as to how enormous it was going to be, and also there's certain dates were given, but it didn't specify where it's going to be," Rep. Peter King, R-N.Y., said.
Officials say the plot is considered "very active" and al Qaeda could change its tactics now that the United States is aware of key details of the planned attacks.
The terror group is now led by Nasar al-Wuhayshi, Osama bin Laden's former personal secretary. He's based in the Arabian Peninsula, home to the most deadly of all the al Qaeda affiliates.
One surprise, according to authorities, is that al Qaeda operatives talked about the plot, possibly knowing it would be intercepted.
"This is a wake-up call," Rep. King said. "Al Qaeda is in many ways stronger than it was before 9/11 because it's mutated and it spread and it can come at us from different directions."
Intelligence officials don't know the exact nature of the threat, but they say al Qaeda has been working for years on bombs that can't be detected... Like liquid explosives or bombs they implant in their own bodies.
"Their expertise is chemical explosives, hitting the aviation sector, as we saw with the underwear bomber. So we are on a high state of alert," Rep. Michael McCaul, R-Texas, told CBS's "Face the Nation."
The U.S. has also issued a travel alert to Americans abroad, warning them to stay away from public transportation and tourist hot spots.
Congressman King says he's seen the intelligence that sparked the embassy shutdown, and this is not some attempt by the Obama administration to deflect the ongoing NSA domestic spying scandal.
The U.S. reopened its embassy and consulates in Israel.