Colombian President Alvaro Uribe has accused leftist rebels of killing 11 kidnapped lawmakers, denying rebel claims the hostages died in the crossfire of a military attack.

President Uribe said in a televised address Thursday that no rescue attempt was made June 18th for the lawmakers, who were kidnapped five years ago.

Mr. Uribe said the rebel Revolutionary Armed Forces of Colombia, or FARC, wants to blame the incident on the armed forces to, in his words, "hide this crime against humanity that it committed." The Colombian military also denied knowledge of the raid.

The U.S. State Department said the people responsible for the deaths of the lawmakers are those who took them hostage. Spokesman Tom Casey called on the rebels to free all their captives, including three Americans.

The 11 hostages reported killed were abducted in April 2002 from the Valle del Cauca departmental Assembly. A 12th lawmaker abducted with them may have survived last week's raid.

The human rights group Amnesty International is calling on the FARC and a smaller rebel group, the National Liberation Army (ELN) to immediately and unconditionally release all civilians being held hostages. Amnesty wants the rebel groups to order their members to assure the humane treatment of those they have captured.

The rights group describes hostage-taking as "a flagrant breach of international humanitarian law, which can constitute a war crime."

Some information for this report was provided by AFP, AP and Reuters.