KARACHI, Pakistan — American drone aircraft fired 18 missiles at militants in Pakistan’s North Waziristan tribal region on Tuesday, killing at least 14 fighters and wounding 4, a security official and a resident of the area said.

The missiles struck a region known as Datta Khel on the Pakistan-Afghanistan border where Taliban and Qaeda fighters prepare for operations against United States and NATO troops in Afghanistan.

The unusually intense drone attack was the third since a failed car bombing in Times Square 10 days ago. Faisal Shahzad, a Pakistani-American charged in the attempted attack, has told American investigators that he visited North Waziristan to train with the Pakistani Taliban. There was no indication that the strikes on Tuesday were retaliation for the bombing attempt.

The attack by the American drones, operated by the C.I.A., appeared to be a continuation of the air campaign to degrade the capabilities of Al Qaeda, the Pakistani Taliban and the Afghan Taliban fighters now working together in North Waziristan.