NEW YORK, May 24 (AFP) - United Nations Secretary General Kofi Annan condemned Monday the kidnapping of a Colombian senator who has been playing a key role in the country's peace talks with leftist guerrillas. A spokesman said Annan hoped that Senator Piedad Cordoba de Castro would be "released soon," and called on Colombian authorities to do all they could to secure her freedom. "The senator, a firm supporter of peace and president of the Colombian Senate's Commission on Human Rights, has performed invaluable work towards the achievement of fundamental rights and freedoms," said UN spokesman Manoel Almeida e Silva. The right-wing Self-Defense Units of Colombia (AUC) claimed responsibility for abducting Cordoba, grabbed in a daring hospital raid on Friday in Medellin, a city some 450 kilometers (280 miles) northwest of Bogota. The group has demanded to participate in peace talks launched earlier this year by conservative President Andres Pastrana, aimed at ending 40 years of civil war in the South American nation. The Colombian government has said it will pay up to 300,000 dollars for information in the case.  