An elite Danish soldier has been killed in southern Afghanistan by an explosive device, military officials said Thursday.

The blast is said to have happened late Wednesday or early Thursday and came as members of Denmark's Ranger and Frogmen units were on a joint patrol with an Afghan police's elite unit.

The Ranger was airlifted by helicopter to a field hospital but his life couldn't be saved. Next of kin have been notified.

The soldier was from the northern Denmark city of Aalborg. His name or rank were not immediately released.

Denmark has about 600 troops in Afghanistan, mostly based in the volatile Helmand province. More than 40 Danish soldiers have been killed in Afghanistan since Denmark joined the U.S.-led coalition in 2002.

Denmark has begun withdrawing its combat units and is gradually shifting its role to training Afghan forces.