Afghanistan ? Militants ambushed a bus carrying construction workers in the country’s volatile south Friday, killing 19 of the laborers, while Afghan and NATO forces said they killed 35 Taliban militants in two separate firefights.

The attack on the bus in Kandahar province began when a roadside bomb exploded near the vehicle, said Zemeri Bashary, the Interior Ministry spokesman. Some laborers may have been killed by the bomb, while others were shot by militants who attacked the panicked workers with gunfire, he said.

Nineteen construction workers were killed and three wounded, Bashary said. It wasn’t immediately known how many people were on the bus or who the laborers worked for.