A small bomb was set off in Neiva, the capital city of south Colombian department of Huila, early Thursday morning, authorities reported.
Property was damaged but no one was hurt, W Radio reported.
The authorities say that the explosion took place close to a church in the suburb of El Jardin.
They did not comment on who they believe is responsible for the blast.
Police also seized 200 kilos of explosives which they allege the FARC were going to use to attack Huila congressional candidates.