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, AP reported.A U.N. 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 U.N. 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.