YAOUNDE, Cameroon 

Doctors without Borders (MSF) late Wednesday denounced the killing of several civilians, including one if its staff members in the Central African Republic (CAR), according to a statement.

MSF said the shooting incident occurred on Dec. 28  on a public transport truck in Grimari city in Ouaka prefecture, southern CAR.

The MSF staff member was severely wounded in the incident which killed a number of passengers and injured several others.

“Once again civilians are caught in the crossfire of a deadly conflict and are victims of an endless cycle of violence,” said Marcella Kraay, MSF's deputy head of mission. 

The situation in the war-torn country is extremely tense since the candidacy of former President Francois Bozize for the Dec. 27 elections was rejected by the Constitutional Council.

Several militia groups, some close to Bozize, have recently attacked civilians, the armed forces and UN peacekeeping forces.

More than 55,000 people have fled violence, according to the UN Office for the Coordination of Humanitarian Affairs.

Recent rebel attacks have prompted UN Secretary-General Antonio Guterres to urge all parties to cease hostilities and ensure peace.

Several towns in the northwest of the country have borne the brunt of fighting between rebel groups and the Central African armed forces.

Last Friday, three Burundian peacekeepers were killed in the CAR, where the rebel coalition broke its cease-fire shortly before the presidential and legislative elections.