BOGOTA, May 21 (AFP) - Unidentified gunmen Friday kidnapped opposition Senator Piedad Cordoba in the northwestern city of Medellin to "send a peace message" according to her three guards, radio reports here said. At least 15 men grabbed Cordoba inside a clinic where she was visiting someone in the exclusive neighborhood of Poblado in the southern part of the city, witnesses said. Cordoba, a member of the Liberal Party of Colombia, is a member of a congressional peace commission and has met several times with leaders of a leftist rebel group in the last few weeks. Her body guards could not say whether the kidnappers were leftist rebels or members of a right-wing paramilitary group. However, the kidnappers said taking Cordoba hostage was meant to send a "peace message" to the government of President Andres Pastrana. After months of stalemate, peace talks between the government and the leftist Revolutionary Armed Forces of Colombia (FARC) resumed earlier this month. -=-=- 