At least five people were killed in overnight clashes in Burundi, police said on Sunday, and residents reported a battle at the president's office in the capital Bujumbura which has been plagued by violence since a disputed presidential election, Reuters reported. Burundi has been in crisis since President Pierre Nkurunziza announced in April he planned to run for a third term - a move opponents said violated the constitution and a peace treaty that ended a 12-year civil war in 2005. Nkurunziza said a court ruling allowed his bid and went on to win a disputed election in July. Residents in Bujumbura's Rohero neighbourhood, close to the president's office, said they heard shooting and explosions overnight. "We heard lot of shootings, explosions and shelling. And it was a kind of exchange of fire between soldiers at the presidency and attackers. Mortars were also fired," a night watchman near the president's office said.