Government troops and warplanes pounded Al Qaeda positions in southern Yemen on Wednesday, killing at least 29 militants as part of a ramped up campaign against the group, military officials said.

Al Qaeda-linked fighters have taken over a swath of territory and several towns in the south, including the Abyan provincial capital of Zinjibar, in the past year, pushing out government forces and setting up their own rule. In recent weeks, the army has launched a concerted effort to dislodge the militants from their strongholds -- and is closely coordinating with U.S. troops who are helping guide the operations from inside Yemen.

On Wednesday, Yemeni airstrikes hit a farm in Moudia, some 25 miles east of the town of Lawder in Abyan, where Al Qaeda fighters were holed up, killing at least 16 militants including top local commander Samir al-Fathani, officials said.

Witnesses said plumes of smoke drifted over the site, which was littered with the charred wreckage of two destroyed vehicles.

Al-Fathani's brother, Abdel-Monem al-Fathani, was involved in the bombing of the USS Cole in October 2000 and was killed in a U.S. airstrike in Abyan in late January.

The fighting is part of a four-front offensive the military began Tuesday, using warplanes and heavy artillery to clear the way for an assault by ground troops on towns where Al Qaeda fighters are either operating or in control. For the first time, Yemen's army is receiving direct help from U.S. troops, who are operating from a desert air base near the main battle zones to help coordinate assaults and airstrikes, according to Yemeni officials.

The officials said it was the most direct American involvement yet in the country's expanding campaign against Al Qaeda's branch in Yemen, which has been blamed for directing a string of unsuccessful bomb plots on U.S. soil from its hideouts in the impoverished country at the tip of the Arabian Peninsula.

On Wednesday, tribal militiamen fighting alongside government forces killed 13 militants who were trying to retake a strategic hilltop, Youssef Mountain, overlooking Lawder. Two militiamen were killed in the fighting, officials said.

On another front in Zinjibar, hit-and-run gunbattles between government troops and Al Qaeda fighters left four soldiers dead, according to a military hospital official.

Also, a security official said a Jordanian surgeon was arrested on suspicion he was heading to Zinjibar to join Al Qaeda.

All of the officials spoke on condition of anonymity because they are not authorized to brief the media.

The fighting in Abyan, particularly around the town of Jaar, has resulted in scores of civilian casualties, the International Committee of the Red Cross said Wednesday. It did not provide numbers.

"We are extremely concerned about the increasing number of casualties and about allegations of airstrikes in civilian locations," said Eric Marclay, the head of the ICRC delegation in Yemen.

The ICRC called on all parties to distinguish between civilians and fighters, and protect health care workers operating in the areas.

In the last three months, the ICRC said it tended to around 100,000 internally displaced people and residents in Abyan, providing them with food and other material.