KABUL — Militants with suicide vests, grenades, and AK-47 rifles attacked a luxury hotel today, killing at least six people in the most brazen attack yet on Western civilians in Kabul, witnesses and a Taliban spokesman said.

Secretary General Ban said the Norwegian foreign minister, who was not hurt, was the target of the assault, which came as the Norwegian embassy was holding a meeting at the Serena Hotel. Two State Department officials said at least one American was among the dead.

It appeared to be the first direct assault on a hotel in Kabul since the fall of the Taliban in 2001. The assailants also appeared to concentrate on the hotel’s gym and spa, where foreigners relax and work out. An American inside said she saw a body she believed to be dead and pools of blood in the lobby.

The militants killed six people and wounded six, an interior ministry spokesman, Zemeri Bashary, said. One of the attackers was shot to death and the Taliban spokesman said a second died in the suicide explosion.

In Washington, two State Department officials said that at least one American was killed. The identity of the victim was being withheld until family could be notified, the official said, speaking on condition of anonymity ahead of a formal announcement of the death.

Earlier, the officials said no American government employees were believed to have been in the hotel when the attack occurred. They said several Americans who had been there had called the embassy in Kabul to say they had not been injured. But the officials could not say if any private American citizens were unaccounted for.