The U.S. military in South Korea has imposed a curfew on its service members as a precaution ahead of anti-American protests planned for this weekend.

The rallies were organized to mark the anniversary of the deaths of two teenage girls who were killed in a 2002 roadside accident involving U.S. soldiers.

A spokeswoman for the U.S. forces in South Korea said a 9 p.m. to 5 a.m. curfew has been imposed from Friday to Sunday.

The accident and subsequent acquittal of the two U.S. GIs charged with accidental homicide prompted a wave of anti-U.S. candlelit vigils by South Koreans.

Thirty-seven thousand-500 U.S. troops are stationed in South Korea under a mutual defense treaty. Crimes committed by U.S. soldiers have been a constant source of anti-U.S. sentiments.