Six people were killed and at least 20 injured after explosives detonated outside a police station in Villa Rica in western Colombia, the Associated Press reported.
At least eighteen police officers were in the station at the time of the explosion, which was caused by homemade mortars and gas cylinders filled with explosives. Among the dead is the commander of the police station, officials told BBC News.
No group has claimed responsibility for the attack. Cauca's state police chief, Col. Ricardo Alarcon, said it was too early to assign blame, but Colombian authorities believe that the Leftist Revolutionary Armed Forces of Colombia (FARC) rebels were responsible, RTT News reported.
The FARC have been stepping up their offensive against Colombian security forces since November, when their leader Cano was killed in a military operation, BBC reported.
More from GlobalPost: FARC rebel leader Cano killed in Colombia
The afternoon attack in Villa Rica came a day after an attack in the southern port city of Tumaco, the AP reported. The bombing on Wednesday killed nine people and wounded 76 outside a police station.
That attack was also blamed on the FARC, RTT reported. Police said the bombing, which involved planted explosives in a tricycle, was meant to target regional police commander Gen. Jorge Nieto Rojas. Rojas escaped the bombing unhurt.
FARC rebels are active in both areas, and frequently use homemade mortars in their attacks, the AP reported.
"What is the FARC looking for?" Colombia's Defense Minister Juan Carlos Pinzon said as he toured Tumaco on Thursday. "Why do they speak in the language of peace but on the other hand commit acts of terrorism like this?"
Pinzon has offered a $670,000 (1,200 million-peso) reward for information that would lead to the capture of the FARC rebel suspected of the attack, who is under the alias Rambo.
More from GlobalPost: Colombian rebels FARC "ready to negotiate"
The FARC have been battling the Colombian government for almost five decades, in Latin America's longest-running insurgency, RTT reported. They want to impose a Leftist regime in the country and redistribute land more equally among Colombians.