"One shipment seized on May 23 along Afghanistan's 580-mile western border contained dozens of anti-tank mines," the report said.
"That's a regular occurrence," Daily Telegraph quoted the official. "It tends to be heavier weapons like mines and mortars rather than Kalashnikovs."
Quantities regularly run into the hundreds and the weapons are usually brand new he added.
Meanwhile, The U.S. military on Wednesday said an air strike in western Afghanistan killed Mullah Mustafa with links to Qods Force of the Iranian Revolutionary Guard Corps (IRGC).