Afghan authorities say a regional police commander and three of his men were killed when their vehicle was hit with a roadside bomb in the country's north.

Baghlan provincial police spokesman Jaweed Basharat said district commander Habinul Rahman was killed Monday when the bomb exploded next to his vehicle while on patrol at about 11 a.m.

Afghanistan's Interior Ministry says roadside bombs are the biggest danger facing security forces in their fight against Taliban militants.