Washington, AP—The top Republican on the Senate Intelligence Committee said the weekend closures of nearly two dozen US embassies and consulates in the Muslim world was “the most serious threat” he’d seen in recent years.

Sen. Saxby Chambliss said Sunday “the chatter” intercepted by US intelligence agencies led the Obama administration to order the weekend closure of 21 diplomatic facilities and to issue a global travel warning to Americans.

He told NBC’s “Meet the Press” that the intelligence was “very reminiscent of what we saw” before the September 11, 2001 terror attacks.

“The one thing that we can talk about is the fact that there’s been an awful lot of chatter out there,” Chambliss said. “We didn’t take heed on 9/11 in a way that we should, but here I think it’s very important that we do take the right kind of planning.”

Rep. C.A. Dutch Ruppersberger, the top Democrat on the House Permanent Select Committee on Intelligence, told ABC’s “This Week” Sunday that the threat intercepted from “high-level people in al-Qaida in the Arabian Peninsula” was about a “major attack.”

The congressman didn’t provide details of the threat, other than to say it came from “people at a high level.”

Rep. Pete King, a Republican who chairs a panel on counterterrorism and intelligence, also spoke to ABC and said that the threat included dates but not locations of possible attacks.

“The threat was specific as to how enormous it was going to be and also that certain dates were given,” King said. He added that while authorities assume any attack is likely to come in the Middle East, warnings to state and local authorities in the US were warranted because of the uncertainty.

“This is a wake-up call,” King said. “Al-Qaida is in many ways stronger than it was before 9/11 because it has mutated and it’s spread in dramatically different locations. And al-Qaida in the Arabian Peninsula is the most deadly of all the al-Qaida affiliates.”

On Friday the Obama administration announced the weekend closures and the State Department announced a global travel alert.

The warning urged American travelers to take extra precautions overseas, citing potential dangers involved with public transportation systems and other prime sites for tourists. It noted that previous terrorist attacks have centered on subway and rail networks as well as airplanes and boats. It suggested travelers sign up for State Department alerts and register with US consulates in the countries they visit. The alert expires on August 31.

The statement said that al-Qaida or its allies might target either US government or private American interests.