BOGOTA - A grenade attack killed three police officers on Monday and injured at least 10 others in Colombia, authorities said Tuesday.

Armed men, believed to be members of the Revolutionary Armed Forces of Colombia (FARC), the country's largest rebel group, launched the attack at a police station in Argelia, a rural area in the southern Cauca province.

The grenade exploded at about 8 p.m. (0100 GMT) when the policemen were eating, killing three officers, Cauca's Governor Guillermo Gonzalez told the local media.

At least 10 other policemen were injured by shrapnel, glass or rock, and were expected to be transferred to a medical center in Popayan, capital city of Cauca.

"But the weather is bad," Gonzalez said, adding that it had not been possible to reach the injured.

Local authorities have started an investigation to determine the details of the attack.

Illegally armed groups in Cauca, including guerrillas, drug cartels, paramilitaries and criminal gangs, have caused an increase in violence in recent years.