BOGOTA, May 22 (Reuters) -- The government blamed Colombia's
                  leading right-wing paramilitary group on Saturday for the kidnapping of a
                  prominent lawmaker and called for her immediate return to freedom.

                  "This is an attack of the gravest kind against democracy and against the
                  longing for peace of all Colombians," the presidential palace said in a
                  strongly worded statement, condemning the kidnapping of Sen. Piedad
                  Cordoba.

                  The statement was issued after President Andres Pastrana huddled with
                  senior aides to discuss a communique read over local radio by Carlos
                  Castano, head of the United Self-Defence Forces of Colombia (AUC), in
                  which he tacitly claimed responsibility for Cordoba's abduction and accused
                  her of openly supporting the country's Marxist rebels.

                  The AUC, Colombia's largest and most dreaded paramilitary group or death
                  squad, has a long history of targeting leftists and suspected rebel
                  sympathisers.

                  "The government reiterates its most emphatic condemnation of the
                  kidnapping of Senator Piedad Cordoba which, according to the
                  communique read by Carlos Castano, was committed by the United
                  Self-Defence Forces of Colombia," the government statement said.

                  "No kidnapping is justified or acceptable and the government demands her
                  immediate release," it said, adding that "acts of force or violence can never
                  be used to sway decisions made about the affairs of state."

                  Cordoba, a member of the opposition Liberal Party and head of the
                  Senate's human rights commission, was abducted on Friday

                  by 15 heavily-armed gunmen in the northwest city of Medellin.

                  In his statement early on Saturday, Castano pressed long-standing demands
                  for recognition of the AUC as a legitimate "political force" and insisted it be
                  invited to take part in the government's fledgling peace talks with
                  Revolutionary Armed Forces of Colombia (FARC) rebels.

                  "We could not remain indifferent in the face of the opportunistic and biased
                  attitude shown by certain personalities and leaders of the Liberal Party, led
                  by Senator Piedad Cordoba, who have placed themselves at the service of
                  guerrilla diplomacy," said the communique.

                  It did not elaborate, but Cordoba, an outspoken critic of paramilitary gangs,
                  has held face-to-face talks with the FARC's commander, Manuel
                  Marulanda, to discuss his demands for the negotiated settlement of a conflict
                  that has taken more than 35,000 lives over the last decade alone.

                  Cordoba, whose kidnapping prompted a public outcry, is also a member of
                  the government's National Council for Peace.

                  In his communique, Castano demanded that the Council ensure that calls for
                  a crackdown on paramilitary groups be stripped from the formal agenda for
                  peace talks agreed earlier this month between the government and the
                  FARC.

                  The FARC, like many international human rights groups, has accused the
                  government and the army of backing outlawed paramilitary gangs as part of
                  a "dirty war" against leftists.