LIMA, Peru (AP) - Peruvian security forces said they believe they have killed two of the four leaders of what remains of the Shining Path rebel group during combat in a coca-growing region in the country's southeast, the president and armed forces chief said Monday. President Ollanta Humana told reporters that DNA tests were being performed to confirm the identities of the top two military leaders of an insurgency the funds itself with the cocaine trade. "Comrade Gabriel" is the nom de guerre of Marco Antonio Quispe Palomino, the youngest of three brothers from the Quispe Palomino clan that commands an estimated 500 fighters. "Comrade Alipio" is Alejandro Borda Casafranca, the group's military chief. (Comrade) Alipio for certain. Still to be determined is (Comrade) Gabriel but it is nearly certain that it is him as well," armed forces chief Adm. Jose Cueto told The Associated Press. The two were believed to be among three rebels killed Sunday night in combat in the Apurimac and Ene river valley region in what Cueto called the culmination of a long manhunt by police investigators and special forces. "They were after them a good long time," he said, crediting human and technical intelligence but without providing immediate details. The Quispe Palomino band is the last remnant of the Shining Path insurgency that devastated Peru from 1980 to 2000. Since 2008, its fighters have killed more than 100 Peruvian troops in the river valley as it's become the world's biggest coca-producing region. In one publicity-grabbing stunt in April 2012, the group's fighters briefly kidnapped 36 construction workers employed in the Camisea natural gas project. This month, it was blamed for destroying heavy equipment used in a road-building project after extortion money went unpaid. Drug experts say Peru has almost certainly supplanted Colombia as the world's No. 1 cocaine-producing country, with much of the product transiting the region where the Quispe Palomino clan holds sway over the local population. Much of the Peruvian product is flown or transported by land, only partially processed, to Bolivia. A smaller Shining Path remnant that operated in the Upper Huallaga valley, another coca-growing region, was dismantled early last year with the capture of its leader Comrade Artemio. He was sentenced to life in prison in June for terrorism, drug trafficking and other crimes. Associated Press writer Carla Salazar contributed to this report.