KABUL, Afghanistan -- A friendly game of basketball between a U.S. and Afghan team turned violent when spectators kicked a fallen American player in the head -- and a guard rushing to protect him unintentionally shot and wounded two Afghans.

The incident Thursday at Kabul's main stadium wasn't the first time an event staged to foster goodwill with Afghans has gotten out of control, and an Afghan sports official suggested the games should be put off until the security situation in the capital improves.

The American squad, which included one British player, pulled out of the four-day basketball tournament with Afghan teams because of the violence.

The game was friendly until an American player running for the ball tumbled near the stands crowded with Afghans celebrating the Persian New Year, said Flight Lt. Tony Marshall, a spokesman for the 4,500-strong international peacekeeping force in Kabul.

Two Afghan spectators kicked him in the head, according to Marshall and witnesses, bringing an Afghan guard from the U.S. Embassy to his defense.

Trying to keep the crowd back, the guard cocked his Kalashnikov rifle, and unintentionally fired off a round as he used it to press back fans, Marshall said.