At least six people were killed on Sunday in the Democratic Republic of Congo during demonstrations across the country against delayed elections — and the de facto continuation of Joseph Kabila’s presidency.

An additional 57 people were injured, and 111 were arrested across the country, according to Florence Marchal, a spokeswoman for the United Nations mission in Congo.

Djafari Akida, who witnessed the events in the capital, Kinshasa, said he had seen five bodies retrieved by the police at the church of St. Gabriel de Yolo, near the airport, where United Nations peacekeepers were present.

He also said several churchgoers at the nearby parish of St. Joseph who had tried to join the demonstrations after Sunday Mass had been shot by the police. Eight people were wounded and taken to a nearby medical facility, he said.

It was the second demonstration in three weeks against Mr. Kabila, whose second presidential term officially expired in December 2016. Nine people died, 98 were injured, and nearly 200 were arrested in similar demonstrations on Dec. 31, according to Ms. Marchal.