NATO soldiers on patrol in eastern Afghanistan Tuesday hit a roadside bomb that killed two of the troops, while NATO said it found and destroyed $400 million worth of opium in the south.

The soldiers were conducting a routine patrol when they bomb went off in the Sharan district of Paktika province, said NATO's International Security Assistance Force.

ISAF did not provide the nationalities of the soldiers.

The latest casualties brings the number of foreign troops killed in Afghanistan to 21 so far this year, according to an AP tally of figures from ISAF and the U.S.-led coalition.

In 2007, more than 6,500 people were killed, including 222 foreign troops. Last year was the deadliest yet since the U.S.-led invasion in 2001.

NATO and Afghan soldiers, meanwhile, discovered and destroyed a massive opium haul during a patrol last week in the Sangin district of southern Helmand province, ISAF said in a statement issued late Tuesday.

The troops found 1.65 tons of opium — which ISAF said was worth $400 million — and a "significant quantity" of drug-making equipment last Thursday, it said. The $400 million figure appeared to be the opium's estimated street value once it was trafficked outside Afghanistan.

Helmand, the front line of the bloodiest battles in recent years between militants and foreign forces, is the world's largest opium-producing region.

PHOTO CAPTION

Map locates Sharan, Afghanistan, where a roadside bomb killed two NATO soldiers.

AP