Guerrillas have killed eight policemen and are occupying a police station in the southern Colombian department of Putumayo, close to the Ecuadorean border.
Putumayo police commander General Orlando de Jesus Polo told Caracol Radio that eight policemen have been killed so far in the raid, which started 4AM local time. Three more police officers are missing.
Authorities are trying to establish if the attack was launched from Colombia, or neighboring Ecuador, which is less than 30 kilometers away.
The national commander of police operations, General Orlando Paez, is travelling to San Miguel and will provide more information when he arrives on the scene.
The police have called for backup from the Colombian army.