An Afghan official says an explosion at a coal mine in the northern province of Samangan has killed at least seven miners.

Hashim Bayan, a spokesman for the provincial police chief, says two other miners were injured in the blast on Monday morning in the remote Dar-i-Suf district.

There has been an increase recently in such incidents in the district as miners work without proper equipment or knowledge of safety measures.

Six miners were killed and another one was injured when an explosion in a nearby coal mine earlier this month caused two tunnels to collapse.

Bayan says people in the area are very poor and have no other options but to work as best as they can in the coal mines to make a living.