The coordinator of the U.N. Communications Group in Congo, Florence Marchal, confirmed a provisional death toll of 18, with 50 others wounded.

Congolese forces have shot and killed at least 18 Burundian refugees near Burundi’s border, officials said on Saturday.

The deaths occurred Friday in the Kamanyola area of Congo’s South Kivu province, the commander of the Pakistani battalion of the U.N. peacekeeping mission in Congo, Waquara Yunusi, told The Associated Press.

Congo’s military could not immediately be reached for comment.

The coordinator of the U.N. Communications Group in Congo, Florence Marchal, confirmed a provisional death toll of 18, with 50 others wounded.

“I do not know the exact circumstances of why it degenerated, but it degenerated ... There were shots from [Congolese forces] and the police on asylum seekers,” she said.

The death toll is likely to worsen, Ms. Marchal said.

The Congolese government, the U.N refugee agency and the U.N. peacekeeping mission in Congo “have deployed teams on site to shed light on everything that happened,” she said.

Burundi’s Foreign Minister, Alain Aime Nyamitwe, on Twitter asked Congo and U.N. officials for an explanation of the shootings.

Residents in the area said the killings occurred after some Burundian refugees went to the bureau of intelligence in Kamanyola to inquire about four detained refugees. Congolese soldiers responded with gunfire when some of the refugees hurled stones, said refugee Aline Nduwarugira.

Another witnesses, Alfred Rukungo, said Congolese soldiers continued shooting into the crowd even after some refugees were wounded.

More than 100 people were injured in the incident, according to Bertin Bisimwa, chief of Kamanyola.

Congo is home to thousands of Burundian refugees. Many fled political violence at home in 2015, when President Pierre Nkurunziza successfully pursued a disputed third term amid deadly protests.