Airstrikes and clashes intensified in southern Yemen on Wednesday as army troops followed major victories with more pressure on al-Qaida militants holding small towns, according to tribal and military officials.
At least 17 al-Qaida militants were killed in the latest phase of Yemen's offensive, they said.
The attacks came a day after Yemeni forces regained control of two major al-Qaida strongholds, Jaar and Zinjibar, which were in the hands of the militants for more than a year.
A monthlong Yemeni government push in the south, aided by U.S. military advisers and bankrolled by neighboring Saudi Arabia, succeeded in driving the militants from two towns.
The U.S. considers al-Qaida's Yemen branch to be the terror network's most dangerous offshoot.
The group took advantage of a security vacuum last year during a popular uprising against Yemen's longtime leader, Ali Abdullah Saleh, to seize swaths of territory in the strategic south. That raised fears it could use the area as a foothold to launch more attacks on U.S. targets.
Yemen's al-Qaida offshoot, known as the al-Qaida in the Arabian Peninsula, has been blamed for directing a string of unsuccessful bomb plots on U.S. soil from its hideouts. It also emerged last month that the CIA thwarted a plot to down a U.S.-bound airliner using a new, sophisticated explosive to be hidden in the bomber's underwear. The planned bomber was actually a double agent who turned the device over to the U.S. government.
The U.S. is helping the Yemenis from a command center manned by dozens of U.S. troops in the al-Annad air base in the southern desert, not far from the main battle zones, Yemeni military officials have said.
The Americans are coordinating assaults and airstrikes and providing information to Yemeni forces, while Saudi Arabia has come forth with cash, especially for armed civilians who back up the Yemeni army in its battles against al-Qaida, Yemeni military officials have said.
In the early hours of Wednesday, airstrikes destroyed a car parked near a house in the town of Azzan, an al-Qaida stronghold in the province of Shabwa, leaving nine al-Qaida militants dead, military officials said. They said the missile was believed to have been fired by a drone. The officials said some militants who fled Jaar have taken refuge in Azzan.
Al-Qaida's propaganda arm claimed in an email message that the attack was launched by a U.S. drone. The Internet-based agency is known to be close to al-Qaida's Yemen branch. There was no U.S. comment.
In separate but coordinated attacks, Yemeni army troops backed by warplanes hit al-Qaida positions north of the town of Shaqra, the last al-Qaida held town in Abyan province. Eight al-Qaida militants and three armed tribesmen backing the army were also killed, officials said.
The army advanced to a hilltop overlooking Shaqra and several other mountain positions after fierce daylong clashes, officials said.
The officials spoke on condition of anonymity in line with army regulations.
After Tuesday's military defeat, al-Qaida remains in control of a handful of towns, and hundreds of its members are scattered in the mountains, valleys and vast desert of the Arab world's most impoverished country.
The militant group said it retreated to "spare bloodshed," threatening to retaliate by attacking Yemen's capital, Sanaa. In an email statement, the group addressed the Yemeni leadership as "crusaders and American agents" and warned, "we will chase you in your cities and palaces."
Tuesday's success capped weeks of fighting after Yemen's new president, Abed Rabbo Mansour Hadi, pledged to uproot al-Qaida from the south with help from the United States as part of renewed cooperation following the resignation of Saleh earlier this year.
With the capture of Jaar and Zinjibar, a senior officer said Yemen's new leadership now has to deal with another front in its war against al-Qaida: sleeper cells that could suddenly attack anywhere.
Brig. Gen. Mohammed al-Sawmali said Tuesday's successes ended al-Qaida's hopes to establish Islamic rule in the south _ but not its presence in the country.
"We expect the group to carry out selective operations targeting key political and military figures," al-Sawmali said Tuesday, speaking from the governor's office in Zinjibar, which al-Qaida had turned into a command post.