"There's no way they'll be able to go in there and use those caves now," said Sgt. Iain Murison from Britain's 59 Commando as a huge, tan dust cloud spread across the desolate hills and valleys of southeastern Afghanistan.
About 220 pounds of plastic explosives, fortified with anti-tank mines, were set off by remote control after people were evacuated from within a mile of the caves.
Ordnance inside the man-made caves continued to explode for hours; at least three rockets shot out and went whizzing across the sky.
"I don't think anyone here has ever even heard of an explosion on that scale let alone been involved in setting it off. It was real spectacular," said Lance Corporal James O'Neill, an engineer with 59 Commando.
He said it was the biggest controlled explosion detonated by British sappers since World War Two.
British forces discovered the cache earlier this week. The caves are 6 to 9 feet high and about 100 to 150 feet deep. Near Soram, south of Gardez, they were hacked out years ago by Muslim fighters and then taken over by the Taliban. Marks from pickaxes were still visible on inside walls.
The caves were sealed shut with metal doors, but at least one was left open — apparently by guards hired by local warlords who fled when the British troops approached, said Lt. Col. Tim Chicken, commander of the 45 Commando.
"You can see things have been moved around recently, but we don't know by whom," he said. "Dust has been disturbed and stuff's been dragged outside."
Sleeping bags had been left there, some of the caves had new padlocks and footprints and tracks around the area seemed fresh.
Chicken said he believed destroying the caves and ammunition stocks was a blow to al Qaeda and the Taliban.
"Al Qaeda clearly have no intention of standing and fighting us man to man but we feel we have succeeded in denying them an important facility here," he said. "There was enough munitions here to keep a small army going for several months and I don't think there's any doubt that the enemy would have come back to use it."
The area near the Afghan border has been beset by factional fighting, including artillery duels between warlords.
Most of the material, stacked from floor to ceiling, was Chinese or Russian-made, Murison said. He estimated the total at more than 20 truckloads, including 30,000 to 40,000 rockets, mortar shells and projectiles.
All of it was destroyed, along with the four caves.
The find came as part of Operation Snipe, a 1,000-man, British-led mission in the mountains of Paktia and Paktika provinces. So far, the troops haven't had any enemy contact.
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