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.
The base, near the Pakistan border, was the site of an attack on Dec. 30, 2009, in which a double agent wearing an explosive vest detonated it inside the facility, killing seven employees of the C.I.A. The Taliban asserted responsibility for that attack, one of the worst casualty losses in the C.I.A.’s history.
It was not immediately clear whether American personnel were at the base on Sunday, since the United States has largely scaled back into a small role of advising the Afghan national security forces.
A senior Afghan official in Kabul said the target of the attack had been the Khost Protection Force, an Afghan unit trained by the C.I.A. but now controlled by the Afghan National Directorate of Security.
The official declined to specify whether American advisers were still assisting the force. But a local security official said American personnel could still be seen at the facility.
An American military official said that no Americans or other members of the multinational military force in Afghanistan were killed or wounded.
Camp Chapman is on the outskirts of the city of Khost, at a busy crossroads connecting several of the province’s districts. The explosion happened about 6:40 p.m., just as residents were making their way home to break their fast for the Muslim holy month of Ramadan.
Gen. Faizullah Ghairat, the provincial police chief, said all casualties of the bombing so far were known to have been civilians.