SANAA, Yemen -- A Yemeni military jet hit three trucks packed with weapons in a restive southern region on Tuesday, killing eight people including suspected al Qaeda militants, military and local officials said.

The trucks were moving arms and ammunition, including artillery equipment, from Shabwa to Marib governorate, where al Qaeda militants have been retreating after the military drove them from nearby strongholds, military officials said. Three of those killed are the drivers of the trucks, while the rest are thought to be al Qaeda fighters, they said, speaking on condition of anonymity because they were not authorized to brief the media.

The strike comes amid an ongoing offensive by the army in southern cities and towns, which has led to the killing and capture of dozens of al Qaeda suspects.

The ministry said that dozens of suspected militants have been killed or captured over the past three weeks, as troops and allied tribal fighters seized a string of al Qaeda-held areas along a 100-kilometre stretch of highway snaking through the rugged desert mountains of the south, starting from the Mahfad region.

The U.S. embassy in Sanaa shut down its premises last week as a precaution against possible retaliatory attacks.

Washington considers Yemen's al Qaeda in the Arabian Peninsula the most active branch of the group in the world, and has assisted the government with logistics, training and drone attacks. The militants have fought back, targeting government buildings and security forces.