Pakistani troops and tribesman shot down a suspected U.S. military drone close to the Afghan border on Tuesday, three intelligence officials said.

It is believed to be the first time that a pilotless aircraft has been shot down over Pakistan.

The incident will likely add to tensions between Washington and Pakistan over a spate of recent American cross-border incursions targeting suspected militants.

The officials said the unmanned aircraft was shot down late Tuesday in the village of Jalal Khel in South Waziristan after circling over the area for several hours. Its wreckage was strewn on the ground, they said, speaking on condition of anonymity because they were not authorized to brief the media.

A U.S. military spokesman in Afghanistan, Capt. Christian Patterson, said officials were looking into the report.

The U.S. is known to operate drones in neighboring Afghanistan that sometimes carry out attacks against suspected militant targets within Pakistan.

Pakistan is not believed to have any of the aircraft, which can be fitted out with missiles and cameras.