Fourteen soldiers of Iran’s Islamic Revolutionary Guard Corps (IRGC) were killed and two others injured while attempting to defuse unexploded ordnance in Zanjan province in northwestern Iran. The incident occurred on Friday, March 1, according to Iran’s military and the Fars News Agency. The explosives were remnants of earlier cluster bomb and aerial mine attacks that had contaminated about 1,200 hectares of farmland in the region.

IRGC specialists had been working for an extended period to clear the area of unexploded weapons, successfully neutralizing more than 15,000 explosive devices before the fatal blast. Iran has previously accused the United States and Israel of using cluster bombs, which disperse smaller explosives that can remain active for long periods.

Iran, Israel, and the United States have not joined the 2008 Convention on Cluster Munitions, which bans the use, production, stockpiling, and transfer of such weapons.