Some 600 Congolese soldiers have fled into Uganda, following clashes with rebels who have seized a border town.The Ugandan military said the fleeing troops had been disarmed.As the rebels took control of the Democratic Republic of Congo side of the town of Bunagana, an Indian peacekeeper was killed, the UN says.M23 rebels loyal to Bosco Ntaganda, who is wanted for war crimes by the International Criminal Court, took up arms in April.They defected from the army after pressure increased on the government to arrest Gen Ntaganda, when one of his former colleagues was convicted of recruiting child soldiers by the ICC.Security sources have told the BBC’s Ignatius Bahizi in Uganda that the M23 rebels control a 15km (10 mile) stretch of the border running south from the famous Virunga National Park, home to rare mountain gorillas.Ugandan army spokesman Capt Peter Mugisa says the 600 Congolese soldiers are in the custody of the Ugandan military. He told the AP news agency they fear being massacred by the rebels if they return.Ugandan residents of Bunagana have told the BBC that the Congolese soldiers have been moved to the town of Kisoro, which is about 8km from the border.Senior M23 official Col Sultani Makenga told the BBC that the rebels had seized the Congolese side of the town early on Friday - information confirmed by residents of the Ugandan side of the town. "The mutineers took control of the entire town. The entire population and the [Congolese] troops are in Uganda,” a police source in the area told the AFP news agency.Col Makenga said the rebels responded after they were attacked by government troops on Thursday.Some 200,000 people have fled their homes since April, with about 20,000 crossing the border to Uganda and Rwanda.The current mutiny is being led by fighters from Gen Ntaganda’s former rebel group the CNDP, which was integrated into the Congolese national army in 2009 as part of a peace deal.Known as "the Terminator”, Gen Ntaganda has fought for various militias over the years but has told the BBC he has no involvement in the recent army mutiny.