ISLAMABAD, Pakistan — Pakistani soldiers and tribesman shot down a suspected American military drone close to the Afghan border, three intelligence officials said.

If verified, the overnight incident apparently would be the first time a pilotless aircraft was brought down over Pakistan and likely would add to tensions between Washington and Islamabad over recent American cross-border incursions into the country’s lawless tribal regions.

The three officials said the aircraft was hit late yesterday at the village of Jalal Khel in South Waziristan after circling the area for several hours. Wreckage was strewn on the ground, they said, speaking on condition of anonymity because they were not authorized to brief the media.

An American military spokesman in Afghanistan, Captain Christian Patterson, said officials were looking into the claim.

The report came a day after intelligence officers said two American helicopters crossed a mile into Pakistan late Sunday over North Waziristan, but flew off after Pakistani troops and tribesmen opened fire. The Pentagon denied any incursion by American helicopters.

While causing widespread anger among Pakistanis, the apparent raids by American forces, including missile strikes and a ground assault, have underlined Washington’s concerns that the government is unwilling or incapable of rooting out the Taliban and other extremists on the border.

America is known to operate drones in neighboring Afghanistan that are sometimes used to conduct surveillance of suspected militant hideouts inside Pakistan and occasionally launch missile attacks on the havens. Washington generally does not acknowledge the strikes, which Pakistani officials say often miss their targets and fuel support for the militants.

South Waziristan and other tribal areas in Pakistan’s northwest are a haven for Al Qaeda and Taliban militants who cross into Afghanistan to attack American and NATO troops as well as for Pakistani extremists who are striking targets in Pakistan.

Militants with roots in the border region are suspected in Saturday’s truck bombing at the Marriott hotel in Islamabad. The attack killed 53 people, among them the Czech ambassador and two U.S. Defense Department employees, and wounded about 270.

Washington is concerned that the Pakistani government is unwilling or incapable of rooting out extremists and wants Islamabad to do more to combat the problem. Pakistan says it has deployed tens of thousands of soldiers to the area and they regularly battle insurgents.