The violent push Tuesday by Houthi rebels against the American-backed government in Yemen is undermining military and intelligence operations against al-Qaida's Yemen-based affiliate, which made its reach felt in this month's deadly Paris attacks, U.S. officials say.

President Barack Obama cited Yemen as a terrorism success story in a September speech outlining his strategy against the Islamic State in Iraq and Syria, which involves targeted U.S. strikes on militants with the cooperation of a friendly ground force. Obama called it an approach "that we have successfully pursued in Yemen and Somalia for years."

But 10 days after the president uttered those words, the Iran-backed Houthi militia swept into Yemen's capital, Sanaa, seizing a share of power. On Tuesday, those same rebels seized the presidential palace and shelled the president's residence, leading Yemeni officials to warn of a coup.

"The government is hanging by a thread," said Rep. Adam Schiff, the ranking Democrat on the House intelligence committee. "This has really scrambled our counterterrorism strategy there and it gives al-Qaida a great new opportunity."

While U.S. officials say the Houthis haven't taken total control, they acknowledge that the government run by their ally, President Abdu Rabbu Mansour Hadi, is more focused now on preserving its power than on running operations against al-Qaida in the Arabian Penninsula. The U.S. considers AQAP the most deadly terrorist threat because of its focus on attacking Western aviation. Two U.S. officials spoke on condition of anonymity because they were not authorized to be quoted discussing intelligence assessments.

AQAP took credit for the massacre at the Paris office of satirical magazine Charlie Hebdo, but U.S. officials say they have no evidence the group had command and control of the operation. They believe the older of the two brothers accused of carrying out the attack traveled briefly to Yemen in 2011. They remain concerned about AQAP's aspirations to attack American aviation with bombs that can't be detected by current screening methods.

AQAP successfully placed three bombs on American-bound airplanes in recent years, but none were detonated. A 2009 attempt to down a passenger jet over Detroit in 2009 went awry, and two printer bombs on cargo planes in 2010 were detected in time. U.S. officials believe the Khorasan Group in Syria is working with AQAP in a plot to smuggle bombs on airplanes in personal electronic devices, and they say air strikes against the group have not ended the threat.

The U.S. embassy in Yemen has long been operating on reduced American staff, but there are an estimated 800 State Department personnel, American citizens and designated foreign nationals in Yemen, plus several dozen Marines guarding the embassy and an unspecified number of special operations forces and CIA officers.

U.S. officials are concerned that the ascendancy of the Shiite Houthis could fuel support for al-Qaida, a Sunni movement that has links to some of Yemen's tribes.

"The sectarian dynamic is likely to become far more problematic, and we learned in Iraq, that's a recipe for disaster," Schiff said.

For several years, the CIA and the military's Joint Special Operations Command have run parallel targeted killing programs in Yemen. There were 23 U.S. drone strikes in Yemen last year and 23 the year before, according to Long War Journal, which tracks the strikes based on local media reports. U.S. special operations forces attempted a hostage rescue in Yemen in April.

The U.S. military also has trained elite counterterrorism units of Yemen's military that have battled al-Qaida.

The Houthis have been fighting al-Qaida in Yemen, so there is a "confluence of interests" between the U.S. and the rebels, said Charles Schmitz, a Yemen specialist at Towson University in Baltimore.

However, the Houthis are deeply anti-American and have gotten support from Iran. In 2013, an Iranian boat seized off Yemen's coast was found to be carrying sophisticated Chinese antiaircraft missiles.

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Associated Press writer Lolita C. Baldor contributed to this report.

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