BOGOTA (AFP) -- Six soldiers were killed Monday in an attack by Revolutionary Armed Forces of Colombia (FARC) guerrillas in southern Colombia, military sources said.

The guerrillas hurled grenades and fired automatic rifles as they attacked an army patrol in a rural area of Cauca department about 700 kilometers south of Bogota, a source with the army's 29th Brigade told AFP.
The rebels killed five soldiers and a non-commissioned officer, the source said, adding that there were no injured reported.
The army was investigating the circumstances surrounding the attack, which was believed to have been carried out by the FARC's Jacobo Arenas column.
With 7,000 to 8,000 fighters, the FARC is the largest guerrilla group operating in Colombia.
The attack came just days after the FARC released six hostages to a peace group led by Senator Piedad Cordoba.
The rebels are holding hundreds of hostages, including 22 military and police that they are seeking to swap for some 500 guerrillas held in Colombian and U.S. jails.