Two American soldiers died in Afghanistan when a roadside bomb they were trying to defuse exploded, US spokeswoman Capt. Elizabeth Mathias said on Sunday.
An Afghan interpreter and a policeman also died in the blast.
A group of American soldiers and Afghan officials were traveling Sunday through the world's largest opium poppy producing region, the southern province of Helmand, when they discovered the roadside bomb and tried to defuse it, said Kamal Uddin, Helmand's deputy provincial police chief.
Top NATO commander Gen. John Craddock said on Sunday that operations to attack drug lords and labs in Afghanistan will begin within the next several days in an effort to strike at a key income source for the Taliban.