WASHINGTON — U.S. diplomatic posts in 19 cities in the Mideast and Africa will remain closed for the rest of the week amid intercepted "chatter" about terror threats, which lawmakers briefed on the information likened to intelligence picked up before the Sept. 11, 2001 attacks.

One lawmaker on an intelligence committee called it the most serious threat he had seen in several years. Another lawmaker said the chatter was specific as to certain dates and the scope of the operation; others said it suggested that a major terrorist attack was being planned by the al-Qaida affiliate in Yemen.

State Department spokeswoman Jen Psaki said the decision to keep the embassies and consulates closed is a sign of an "abundance of caution" and is "not an indication of a new threat."

Diplomatic facilities will remain closed in Egypt, Jordan, Libya, Yemen, Saudi Arabia and Kuwait, among other countries, through Saturday, Aug. 10. The State Department announcement Sunday added closures of four African sites, in Madagascar, Burundi, Rwanda and Mauritius.

The U.S. decided to reopen some posts on Monday, including those in Kabul, Afghanistan, and Baghdad.

The intelligence intercepts also prompted Britain, Germany and France to close their embassies in Yemen on Sunday and Monday. British authorities said some embassy staff in Yemen had been withdrawn "due to security concerns." France said Monday it would extend the closure of its embassy in the Yemeni capital through Wednesday.

Interpol, the French-based international police agency, has also issued a global security alert in connection with suspected al-Qaida involvement in several recent prison escapes including those in Iraq, Libya and Pakistan.

The Obama administration announced Friday that the posts would be closed over the weekend and the State Department announced a global travel alert, warning that al-Qaida or its allies might target either U.S. government or private American interests.

The intercepted intelligence foreshadowing an attack on U.S. or Western interests is evidence of one of the gravest threats to the United States since the Sept. 11, 2001 attacks, according to several lawmakers who made the rounds on the weekend talk shows.

"This is the most serious threat that I've seen in the last several years," Sen. Saxby Chambliss told NBC on Sunday. "Chatter means conversation among terrorists about the planning that's going on — very reminiscent of what we saw pre-9/11."

Chambliss, the top Republican on the Senate Intelligence Committee, said it was that chatter that prompted the Obama administration to order the Sunday closure of 22 embassies and consulates and issue a global travel warning to Americans.

Congressman C.A. Dutch Ruppersberger, the top Democrat on the House of Representatives Intelligence Committee, told ABC that the threat intercepted from "high-level people in al-Qaida in the Arabian Peninsula" was about a "major attack."

Yemen is home to al-Qaida's most dangerous affiliate, blamed for several notable terrorist plots on the United States. They include the foiled Dec. 25, 2009 effort to bomb an airliner over Detroit and the explosives-laden parcels intercepted the following year aboard cargo flights.

Congressman Peter King, the Republican who leads the House Homeland Security subcommittee on counterterrorism and intelligence, told ABC the threat "was specific as to how enormous it was going to be and also that certain dates were given."

Friday's warning urged U.S. 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 U.S. consulates in the countries they visit. The alert expires on Aug. 31.

The Obama administration's decision to close the embassies and the lawmakers' general discussion about the threats and the related intelligence discoveries come at a sensitive time as the government tries to defend recently disclosed National Security Agency surveillance programs that have stirred deep privacy concerns and raised the potential of the first serious retrenchment in terrorism-fighting efforts since Sept. 11.