The footage showed aerial views of the two destroyed outposts, Boulder and Volcano, and close-ups of the site White smoke could be seen spiralling from large swathes of blackened ground either side of the remote rocky mountaintop where both posts were situated. Army spokesman Brigadier Syed Azmat Ali said the smoke was a result of the nearly two-hour incident in the early hours of Saturday. The footage was filmed on Sunday morning, he said. It was not clear why it had taken until Wednesday to release. Scattered sandbags, tarpaulin sheets and corrugated iron sheets can be seen lying around one of the abandoned posts, and Pakistani soldiers wander through the wreckage, one taking photographs. A single white flag flies from a branch stuck in the soil. In another shot a stone hut can be seen, metres (yards) from the remains of a rock wall, next to which magazines of ammunition have been abandoned. US Secretary of State Hillary Clinton on Wednesday pledged an investigation "as swiftly and thoroughly as possible" into the "tragic incident" but stopped short of apologising for the deaths.