Helicopters left this city on Saturday to ferry rescuers to an isolated corner of Colombia to treat survivors of battles between rebels and paramilitary fighters that killed at least 60 people — most of them reportedly civilians.

Gen. Leonel Gomez, commander of the army's 1st Division, told reporters Saturday that the medics on the helicopters would try to treat and evacuate 16 of the most seriously injured people to a hospital in Medellin, Colombia's second-largest city.

The fighting began Wednesday in Choco state when 500 fighters of an outlaw paramilitary militia squared off against 800 members of the leftist Revolutionary Armed Forces of Colombia, or FARC, for control of lucrative drug-producing territory, said Gomez.

The acting governor of Choco state, David Mosquera, said it appeared that most of the victims were civilians killed on Thursday when the FARC fired homemade mortars into a church in Bojaya -- 235 miles northwest of the capital, Bogota.

Residents also reported that more bodies have been found in a swamp and a stream outside the township, Mosquera said, adding that the death toll could climb to 80.

It was not immediately clear if rebels were aiming at the church. Rebels use cooking gas canisters packed with explosives as mortar rounds, which are not accurate.

Mosquera said hospital officials reported 60 dead and dozens injured in the clashes. Colombia's national human rights ombudsman, Eduardo Cifuentes, said his staffer in the region had reported the same casualty figure.

Cifuentes blamed the tragedy on the lack of government forces. Neither the army nor national police maintain a permanent presence in the area, which has become a battleground for the rebels and the rival right-wing militia.

The team of 10 doctors and paramedics that left in helicopters arrived in the zone Saturday afternoon, according to the Red Cross. The Red Cross sent its own rescuers to the area by boat.

Colombia's civil war pits the FARC and a smaller rebel group against the paramilitaries and government forces. Roughly 3,500 people are killed in fighting each year.

The jungle-covered area around Bojaya village is reachable only by air or the Atrato River, and the rebels and paramilitaries were reportedly fighting for control of the waterway.

Rescue services hoped to fly to the region's airstrip on Friday but fighting prevented them from making the attempt.