The two men were turned over by National Liberation Army (ELN) guerrillas in a rural part of northeast Colombia to a humanitarian team that included ICRC delegates, the aid group said in a statement.

The men were identified as Uwe and Otto Breuer, brothers aged 69 and 73.

They were kidnapped four months ago in the same region of Norte de Santander department where they were released Friday.

"We're glad that the two men have been freed and will soon be reunited with their families," said Jordi Raich, head of the ICRC delegation in Colombia.

"It's gratifying to be of service in this kind of operation. As an impartial, neutral and independent intermediary between all the parties to the conflict, the ICRC is always keen to help relieve the suffering of people who have been deprived of liberty."

The ICRC did not immediately indicate the former captives' physical condition.

They were flown by helicopter to the city of Ocana, where they were turned over to German embassy officials before heading to the capital Bogota on a plane.

Rebels initially accused the Germans of being spies, but later asked that a humanitarian commission be formed so they could be handed over.

The ELN is Colombia's second largest rebel army, with an estimated 2,500 fighters.

The FARC, the country's largest guerrilla group with an estimated 8,000 fighters, is holding peace talks with the government.