SANAA, Yemen (AP) — Soldiers backed by fighter jets and tanks pushed further Thursday into southern Yemen as part of an ongoing offensive targeting its local al-Qaida branch, military officials said, an operation that has killed 25 suspected militants and 12 security force members.

The offensive began Tuesday along three fronts in the remote Mafhed mountains of Abyan and Shabwa provinces, officials said. They say that among those killed is a foreign national from Uzbekistan named Abu Mussalam al-Uzbeki, in addition to an alleged al-Qaida leader in the region.

The military's claims could not be immediately verified. Yemen's government previously has claimed to have killed leading militants who later turned out to be alive.

A military statement said al-Qaida militants surprised military forces by attacking a town called al-Majaala behind the front lines, though soldiers later took back the town. It added that the forces dismantled land mines and captured vehicles used by al-Qaida militants, as well as arrested a number of suspected fighters

Al-Majaala witnessed one of the deadliest strikes in the ongoing U.S. drone campaign in Yemen. In 2009, a strike there killed dozens of people and sparking an international outcry against the use of drones over civilian casualties.

Military officials say forces also faced stiff resistance in Shabwa as militants fired mortars and artillery at soldiers.

The officials spoke on condition of anonymity because they were not authorized to speak to journalists.

Washington considers Yemen's al-Qaida in the Arabian Peninsula as the world's most dangerous branch of the terror network. The group is blamed for a number of unsuccessful bomb plots aimed at Americans, including an attempt to bring down a U.S.-bound airliner with explosive hidden in the bomber's underwear and a second plot to send mail bombs hidden in the toner cartridges on planes headed to the U.S.

The United States has been hitting suspected al-Qaida positions in the country with drone strikes over the past two years, trying to cripple the group after it was driven out of several southern cities it took over in 2011.

But the group has proved highly resilient. A video recently posted on Islamic militant websites showed the group's leader, Nasser al-Wahishi, meeting openly with dozens of militants in Abyan.