Peacekeeping soldiers from Chad opened fire on civilians in the strife-torn capital of the Central African Republic over the weekend, killing more than 30 people and sparking fears of reprisal attacks, officials and witnesses said.

Jean-Pierre Sadou, an official with the regional peacekeeping mission could not confirm the death tolls in Bangui provided by local officials but said the soldiers acted in a "legitimate defense" after an attack on their convoy.

The soldiers were returning from a mission in the country's interior on Saturday when two of their vehicles were hit by grenades, said Sadou. In response, the soldiers forced their way past a roadblock erected by French soldiers in Bangui's PK12 neighborhood and started shooting into the crowd, witnesses said.

More than 20 people were killed in the PK12 neighborhood alone, said Odette Dombolo, a commune mayor.

"We continue to collect the bodies," Dombolo said Sunday. "There are more than 100 injured, and I mean seriously. We are overwhelmed."

The same soldiers killed four people in the Gobongo neighborhood, local official Jean Claude Yamodo said, and witnesses said eight more people were killed near the airport.

Central African Republic, long one of the world's poorest and most unstable countries, descended into chaos one year ago when an alliance of mostly Muslim rebel groups in the country's north overthrew Francois Bozize, who had been the president for a decade. The rule of the Muslim rebel coalition known as Seleka was marked by atrocities, including tying together victims and throwing them off bridges into rivers to drown or be eaten by crocodiles.

Michel Djotodia, the rebel leader-turned-president, stepped down from power in January amid mounting international pressure. Since then, the country's Muslim minority population has been targeted in often brutal retaliatory violence at the hands of a Christian militia known as the anti-Balaka. Tens of thousands of Muslims have fled for their lives in convoys to neighboring Chad.

All civilians in Bangui are threatened by daily attacks, said the U.N. children's agency. Saturday's violence in the city came just one day after suspected Muslim rebels launched a grenade attack on a funeral, killing at least nine people.

It’s unclear how many have been killed in the country since violence started in December. More than 1,000 people were killed in that month alone, but it’s unknown how many hundreds or thousands of casualties have occurred since then.

The U.N. estimates at least 1 million people have been displaced from their homes because of the violence.

The U.N. is in the midst of trying to convince member nations to send a larger peacekeeping force to the country, but even if the U.N.’s calls are heeded, it could take months for those troops to arrive.

France has sent about 2,000 troops and the African Union has sent 6,000 troops, but U.N. officials say many more are needed to help contain the violence.

Al Jazeera and wire services