One day after the Yemeni authorities took credit for disrupting a terrorist plot against oil and gas lines there, the White House continued to rigorously defend the administration's decision to keep a record numbers of embassies around the world shuttered with no end in sight to the closures.

U.S. officials are remaining on high alert and will continue to keep 19 diplomatic facilities in the Middle East, Northern Africa and Central Asia shuttered as intelligence agencies evaluate the threat level.

"I think there will be an assessment, and when there's an assessment that this current threat is not what it was, then we'll probably change our posture," White House spokesman Jay Carney told reporters at his daily briefing Thursday. "But I certainly don't have a timeline to predict for you."

The Yemeni government on Wednesday said it had thwarted plans by al Qaeda to attack a strategic southern port's oil and gas facilities and to kill or kidnap foreigners working at the sites.

The announcement, however, did not prompt the State Department to reopen any closed facilities, spurring questions about when the U.S. government will feel like the threat has dissipated enough to allow U.S. personnel in hot spots around the globe to return to their jobs.

It's a classic "damned-if-you-do, damned-if-you-don't" scenario for an administration experiencing renewed scrutiny about its handling of embassy security and the aftermath of the Benghazi attack as the deadly assault's one-year anniversary approaches.

The State Department's travel warnings, issued Aug. 2, told Americans to be wary of visiting troubled areas of the world through the end of August. President Obama, appearing on the "Tonight Show" with Jay Leno, seemed to downplay the threat, if ever so slightly, by encouraging Americans to still "live their lives" and travel to destinations within reason.

Still, with Sept. 11 and the one-year anniversary of the Benghazi attack just around the corner, it's likely that U.S. officials will want to err on the side of caution and keep the embassies closed for weeks, if not longer.

"Every single day, we make decisions about how to keep the men and women who serve around the world safe, how to keep Americans safe, how to keep visitors to our embassy safe," State Department spokeswoman Jen Psaki told CNN Wednesday afternoon. "... We have remaining concerns about threats, and we have not made an announcement to reopen the embassy, but we continue to evaluate."

Major concerns about terrorists' potential use of a new generation of liquid explosive that the Transportation Security Administration cannot detect also has intelligence officials on edge, according to ABC News. The technique, developed by the Yemen-based al Qaeda affiliate in the Arabian Peninsula (AQAP), allows terrorists to dip ordinary clothing into a liquid to make the clothes themselves into explosives once they dry.

Obama and the White House this year have claimed that they have decimated the "core" of al Qaeda, reducing the changes of a repeat 9/11-style attack. But national security experts say that terrorist groups have evolved after surviving more than a decade of drone attacks and counter-terrorist operations, and they present what the Center for Strategic and International Studies' Thomas Sanderson calls "a far more sophisticated, seasoned opponent than before."

"Terrorists understand that hierarchical organizations are vulnerable to disruption, while smaller organizations, distributed operations and partnerships can make a deep impact," he said in a question-and-answer interview posted on the CSIS website.

U.S. security officials have pinpointed Yemen as the focal point of a likely attack. AQAP suffered a serious blow over the last year as Yemeni forces, under Yemeni President Abd Rabbuh Manur Hadi's direction, launched military attacks that ended al Qaeda's control of the southern region and pushed it up into the hills.

Launching an attack around the time of Hadi's visit to the United States, which took place Aug. 1, would prove to be a public-relations coup for the AQAP.

The Obama administration also wants to demonstrate its power to fight back after enduring a week of criticism that the world's biggest superpower has been forced into a defensive crouch. On Thursday, three U.S. drone strikes killed a total of 12 suspected al Qaeda militants, bringing to eight the number of U.S. attacks in Yemen in less than two weeks.