At least 56 people were killed in fresh clashes between government and opposition forces near the northern town of Malakal in South Sudan, an official here said.Brigadier General Lul Ruai Koang, Sudan People's Liberation Army spokesman, told the media on Sunday that the fighters linked to former Vice President Riek Machar attacked two government bases near Malakal on Friday evening.Koang said 56 rebel fighters were killed and dozens of weapons seized, Xinhua news agency reported."They attacked us on the western side of the Nile. Over 56 rebels were killed," Koang said.A local area commander, Butrus Bol Bol, told Xinhua that the rebels attacked their bases at Worjok and Alelo, West of the River Nile.