MONROVIA, March 2 (Xinhua) -- The Liberian National Police (LNP) has announced the imposition of a curfew in the northern Liberian city of Voinjama, after clashes broke out between Christians and Muslims over the weekend.

Marc Amblar, director of the LNP, said the curfew will run from 6:00 p.m. local time to 8:00 a.m. local time and will remain enforced until further notice.

Amblar told reporters on Sunday that he had given strict instructions to riot police dispatched to the area to restore calm while dealing harshly with anyone in violation of law or curfew.

According to him, four people were killed and 21 others severely injured in Friday's violence. Several rioters have been rounded up and taken in police custody.

The Liberian police chief said his men have seized five single- barrels guns and seven machetes.

Meanwhile, Galakpai Kortimai, superintendent of the troubled Lofa County, told Xinhua on Sunday that calm returned to the area following the violence.

Kortimai said shops and stores have once again opened their doors to customers and commercial activities were returning to normal.

He claimed that local officials embarked on a massive campaign urging residents not to panic, but to return to their homes as the situation was brought under control.

Violence flares in the northern Liberian town, which change hands several times among warring factions after the body of a girl was discovered in the area.

The death of the deceased was blamed on some Muslims, who were accused by some local residents of masterminding the alleged act for ritual purposes to open a newly constructed mosque.