Bogota - Colombia's army chief General Mario Montoya on Tuesday resigned over the scandal around the alleged murder of 23 civilians by the military.

Last week, President Alvaro Uribe suspended 27 soldiers, including three generals, on suspicion of human rights crimes.

In possibly the worst case of human rights violations by Colombia's armed forces in years, the judiciary found the 23 victims - members from a gang - had been kidnapped in the capital Bogota at the beginning of the year. They were later presented as members of an armed group killed in clashes with the military in the north of the country.

At least 1,122 such deaths have been reported in the past five years. Uribe has said he will no longer give military honours based on the number of opponents killed.

Defence Minister Juan Manuel Santos, whose resignation the opposition has called for, was due to respond in parliament on Tuesday.

Human rights groups and churches have long been complaining that soldiers sometimes indiscriminately drag civilians from their homes in poor neighbourhoods, shoot them and later present them as slain combatants.

United Nations High Commissioner for Human Rights, Navi Pillay, also expressed concern over the killings during a visit, saying authorities urgently needed measures to prevent such crimes and punish the perpetrators. (dpa)