A U.S. airstrike on Tuesday killed scores of people in southern Yemen, an attack that one analyst says may represent a new approach to the administration’s “targeted killing” program.

The Pentagon said in a statement that the target of the attack was an al-Qaeda in the Arabian Peninsula (AQAP) training camp, adding, “our initial assessment is that dozens of AQAP fighters” were killed.

The statement gave not detail about potential civilian casualties.

According to Yemeni sources on Wednesday, the death toll was at least 50, with another 30 wounded, Reuters reports.

The deadly strike comes hours after two men carried out coordinated attacks striking the airport and a metro station in Brussels that left over 30 people dead.

The U.S.’s latest strike on Yemen would make it “the bloodiest attack there by Washington for more than five years,” the Bureau of Investigative Journalism reports, citing the December 2009 by a U.S. cruise missile loaded with cluster bombs that killed at least 55 people, the majority of whom were civilians.

The new strike comes the same month as a combination of U.S. drone and air strikes in Somalia killed 150 people labeled by the Pentagon as “fighters”—an unprecendented death toll in U.S. counter-terrorism efforts.

The pair of U.S. strikes this month may offer clues about a changing approach by the Obama administration to killing supposed terrorists.