GOMA, Congo — An explosion while a group of Indian peacekeepers were exercising in eastern Congo on Tuesday morning killed a young girl, injured 32 peacekeepers and sparked an angry demonstration that was dispersed by tear gas, U.N. officials and witnesses said.

U.N. spokesman Stephane Dujarric told reporters at U.N. headquarters in New York that five of the peacekeepers were seriously hurt but none were killed.

U.N. Secretary-General Ban Ki-moon condemned the attack and called for “swift action” to bring the perpetrators to justice, Dujarric said.

Julien Paluku, governor of North Kivu province had said earlier that one peacekeeper and an 8-year-old child were killed and three civilians were injured in the blast in the outskirts of Goma.

Dujarric said that according to preliminary reports the explosion was caused by an improvised explosive device that detonated while the peacekeepers were on a morning run. Earlier, officials said a grenade had detonated.

Dujarric said all the injured peacekeepers and civilians were receiving medical treatment in Goma.

The U.N. peacekeeping mission in Congo sent a quick reaction force and an investigation team including explosives experts to the scene, Dujarric said.

“The staff is very busy gathering information about this incident,” said Sylvestre Kilolo, a spokesman for Congo’s U.N. mission.

Various rebel groups are active in Congo’s northeast, though most recent violence has occurred in the Beni region north of Goma.