"One German soldier was killed and another one injured," when their vehicle made contact with the explosive device at around 1:00 pm (0830 GMT), Lieutenant Colonel Paul Kolken told AFP.

"The injured soldier was medically evacuated by helicopter to Camp Warehouse Multinational Brigade hospital," he said, referring to the main ISAF base in Kabul. The soldier had been treated and was in stable condition.

"A third soldier trapped within a suspected minefield was rescued," he said.

The blast occurred when the troops were on patrol along a track 15 kilometres (10 miles) south of Camp Warehouse, in southeast Kabul, Kolken said.

German Defence Minister Peter Struck said the incident appeared to have been an accident.

"There is no indication of an attack," Struck said at a press conference in Berlin.

It was not immediately known whether it was old mine or a new, deliberately laid one, Kolken said.

An investigation was underway and next of kin had not yet been informed, he said. No further details were immediately available on the blast which occurred in Butkhak district, an area of small villages on the outskirts of the city.

After 23 years of war, Afghanistan is one of the most heavily mined countries in the world, with unexploded ordnance responsible for maiming or killing hundreds of people every year.

In a statement issued shortly after the incident, the peacekeeping force described the death as "saddening".

"This tragedy, coming whilst ISAF is still grieving the loss of 62 Spanish colleagues, has saddened the military community greatly," it said.

The Spanish troops were killed in a plane crash in Turkey on Monday while flying home after a four-month tour of duty in Afghanistan.

Some 2,300 German troops serve with the ISAF, which is currently under joint German-Dutch command.

Thursday's death brings to 76 the total number of ISAF personnel killed on active service since the peacekeeping force was established in December 2001 following the fall of the Taliban.

Seven ISAF troops died in an earlier helicopter crash, five were killed while dismantling rockets and an Afghan interpreter working for ISAF was also killed.

ISAF is responsible for security in Kabul under a United Nations mandate following the fall of the Taliban regime in late 2001.

Some 29 nations contribute to the 4,600 strong force.

Canada will contribute 1,800 troops from July and will take over command of ISAF's main base. An advance party of Canadian troops has already arrived in Kabul.

NATO is due to take over command of ISAF when the six-month lead term of the current German-Dutch command expires in August.

WAR.WIRE