Colombia's military has blamed militants from the rebel ELN (National Liberation Army) group for two bomb attacks, one of which destroyed a bridge over the River Simana.
No deaths or injuries were reported from the attacks.
The first bomb went off at the Amarillo bridge over the Simana River, cutting off access to vehicles. The bridge connects the country's Atlantic coast with its inland.
The second attack took place in the northeastern Curumani region.
The ELN, which is thought to have a fighting force of 2,000 people, agreed a first-ever ceasefire with government in October.
But President Juan Manuel Santos suspended peace negotiations earlier this year after a series of rebel attacks killed at least seven police over one weekend.
Colombia's government suspended peace negotiations with the ELN after a series of rebel attacks killed at least seven police officers earlier this year.
The government signed a peace deal with a larger guerrilla group, the Revolutionary Armed Forces of Colombia (FARC), in late in 2016. The group is now a political party.