At least five dissident members of the former FARC guerrilla group have been killed in a military operation in southern Colombia, the army announced Monday. It said the rebels belonged to the Nueva Marquetalia group led by Ivan Marquez, a former leader of FARC, or the Revolutionary Armed Forces of Colombia. Marquez was the group’s chief negotiator in the 2016 talks with the government that led to a historic peace agreement and to the disarmament of 13,000 rebels. But three years later, Marquez announced he was again taking up arms, saying the government had failed to respect the deal signed in Havana. The latest military operation was carried out in Caqueta department in the country’s Amazonian south, an area where military and civilian officials blame FARC for a series of recent massacres. The loosely organized FARC now has some 2,500 fighters under arms, largely financed by drug trafficking, illegal mining operations and extortion, according to military intelligence officials.