The United Nations peacekeeping mission in Congo says explosions from an arms depot near the diamond-mining hub of Mbuji-Mayi have killed more than 20 people.
A UN statement says the explosions injured 50 people and destroyed many houses, causing "desolation" in the heart of Congo's third largest city.
It says "official sources" determined that a lightning bolt on Friday hit the munitions depot of an army barracks outside Mbuji-Mayi and exploding shells hit homes some 6 kilometers (4 miles) away.
U.N. mission chief Martin Kobler said he had instructed the UN office in Mbuji-Mayi to provide support to local authorities, and he commiserated with victims.
In neighboring Republic of Congo a fire set off war-grade weapons at an arms depot in the capital that killed nearly 300 people in 2012.