An American drone strike targeted the leader of the Taliban, Mullah Akhtar Muhammad Mansour, in Pakistan near the border with Afghanistan, United States officials said on Saturday, in the most significant American incursion inside Pakistan since Navy SEALs killed Osama bin Laden, the Qaeda leader, in 2011.

A suicide car bomber killed at least 25 people and wounded 15 on Sunday outside a United States base in Afghanistan s southeastern province of Khost, the site of a suicide attack in 2009 that left seven C.I.A. operatives dead. Provincial security officials in Khost said the car bomber had intended to penetrate the base, Camp Chapman, a major facility at the height of the American military presence, also known as Forward Operating Base Chapman.