American officials said on Wednesday that Mr. Mohammad had been killed with about 12 other insurgents in what the C.I.A. calls a “signature strike,” an attack based on patterns of activity, such as men toting arms in an area controlled by extremist groups. Such strikes have prompted the sharpest divisions inside the Obama administration, with some officials questioning whether killing unidentified fighters is legally justified or worth the local backlash…

While Mr. Mohammad was not directly targeted, he had come under increasing scrutiny by American counterterrorism officials, who said he was involved in recruiting militants for Al Qaeda and the Pakistani Taliban, as well as making videos on YouTube to incite violence against the United States.

“He had risen to the top of the U.S. deck,” said Seth G. Jones, a senior political scientist at the RAND Corporation and former adviser to the military’s Special Operations Command. Mr. Jones said that while in Pakistan, Mr. Mohammad had made contact with five young Virginia men who disappeared from their homes around Thanksgiving in 2009 and turned up seeking to join militant groups. Instead they were arrested and remain in Pakistani custody.