(Adds background) KINSHASA, March 22 (Reuters) - U.N. peacekeepers in Congo evacuated more than 450 civilians from their homes and offices in a district of the capital Kinshasa late on Thursday after fierce gunbattles, a senior U.N. official said. "So far we have evacuated 450 people," the official from the U.N. mission in Congo (MONUC) told Reuters, asking not to be named. The civilians, some of whom were injured, were taken in armoured personnel carriers to MONUC's headquarters in Kinshasa. Gunfire and explosions rang out earlier on Thursday as armed followers of former rebel leader Jean-Pierre Bemba fought government troops in the first clashes in Democratic Republic of Congo's capital since landmark elections last year. The shooting broke out after Bemba's personal militia defied a government order last week to disband after the polls, meant to bring peace to the vast, war-battered central African nation. It was not immediately clear who was being taken to the MONUC headquarters but the U.N. mission has agreements to evacuate individuals, including senior diplomats and their families, in the event of fighting in Kinshasa. Buildings including a downtown hotel popular with foreigners had been looted in the violence, a second U.N. source said.