By Patrick Markey BOGOTA, Colombia, Oct 25 (Reuters) - Washington wants to extend anti-drug initiatives with Colombia but will urge its Andean ally to curb rights abuses and question whether disarmed militia leaders are facing justice, a top U.S. official said. U.S. Undersecretary of State Nicholas Burns said the Bush administration was in talks on extending the Plan Colombia program to fight the cocaine trade and fund the military in its conflict with rebels battling a four-decade insurgency. President Alvaro Uribe has driven back the Revolutionary Armed Forces of Colombia, known as FARC, but his military has faced fire over abuses. Soldiers have been accused of killing civilians and of collaborating with illegal armed groups. "We think the counter-terrorism and counter-narcotics efforts have been very successful but there could be further progress," Burns told Reuters late Tuesday during a visit to Bogota for talks with Uribe. "If the military is responsible for human rights violations then those people need to be held accountable, they need to be prosecuted," he said. A U.S.-trained attorney, Uribe is one of Washington's staunchest allies in Latin America. He has received millions of dollars in U.S. aid to fight left-wing guerrillas and the illicit drug trade that helps fuel violence that kills or drives thousands of people from their homes each year. A quarter of U.S. aid for the Colombian military is conditioned on its human rights record, which must be certified by the United States before the funds can be released. The United States under the Clinton administration signed the five-year, multi-billion-dollar Plan Colombia, which expired last year. Some U.S. officials had said Washington wanted to reduce anti-narcotics aid after the plan lapsed. But Burns said the Bush administration would ask Congress to keep funding for Colombia with about $600 million a year through at least 2008 and discuss with Uribe the possibility of continuing the Plan Colombia initiative. The funding comes even as some critics question how effective the U.S.-backed program has been in eradicating Colombia's coca leaf production, which supplies 90 percent of the cocaine consumed in the United States. GUARANTEES FOR JUSTICE As part of his peace plan, Uribe has negotiated the demobilization of about 30,000 illegal right-wing paramilitary fighters who were established in the 1980s by rich landowners and cocaine traffickers to battle the rebels. Accused of some of the conflict's worst massacres and abuses, paramilitary leaders have handed over their weapons in exchange for short jail terms, confessing to crimes and offering reparation to victims. Some of the top militia leaders, who have been accused of drug trafficking, torture and kidnapping, have had U.S. extradition warrants suspended as part of the peace deal with the Uribe administration. But human rights groups say the former warlords have been allowed to get off easily and have kept their criminal networks intact even as they enjoy the benefits of the justice law that allowed the peace deal. Hundreds of fighters also have left the program to return to crime, the government acknowledges. "We think this is a necessary law ... we are in favor of the effort but there are some questions about whether some of sentences are too lenient, whether people who are responsible for horrible crimes are getting off too easily," Burns said. "It is up to Colombia to work through that but as we are funding some of these programs these questions are being asked," he said.