BOGOTA, Aug. 15 (Xinhua) -- A bomb explosion has killed seven people and injured more than 50 others in northwestern Colombia, police said Friday.

　　The explosion occurred Thursday night in front of a discotheque in central Ituango in Antioquia province.

　　The injured, of whom 14 were in critical condition, were taken by helicopter to Antioquia's capital Medellin early Friday morning.

　　Police said the armed group "El Pajaro," supposedly a faction of the rebel Revolutionary Armed Forces of Colombia (FARC), was responsible for the attack.

　　A person connected to the blast has been detained, the provincial police commander said.