Al-Qaeda-linked fighters took advantage of Yemen's 2011 uprising to overrun a swath of territory and several towns in the south, pushing out government forces and establishing their own rule. In recent weeks, the army has launched a concerted effort to uproot the militants from their strongholds - and is closely coordinating with a small contingent of U.S. troops who are helping guide the operations from inside Yemen.
Officials say U.S. drones have been providing information to their forces.
The military officials said Yemeni warplanes pounded targets some three miles outside Jaar. Up to 70 percent of Jaar's residents have fled the town during the past months to escape the fighting.
The officials, who spoke on condition of anonymity in line with military regulations, said the militants used suicide car bombing against military checkpoints and vehicles to hinder the army's advance and had called for reinforcements from neighboring towns.
Yemen's new president, Abed Rabbo Mansour Hadi, took office in February as part of a U.S.- and Saudi-backed deal aimed at ending the unrest. He has made fighting al-Qaeda one of his top priorities.
The official news agency SABA said Maj. Gen. Ken Tovo, a U.S. commanding general of special operations, met Saturday with Yemen's chief of staff Maj. Gen. Ahmed Ali al-Ashwal and discussed U.S. aid to Yemen in combating terrorism and the fight against al-Qaeda.