A truck loaded with explosives detonated outside a police headquarters in Cucuta, Colombia, early Saturday morning, wounding 14 people and killing a police dog, six days before the country is set to swear in a new president.

The blast struck the building that serves as police headquarters for Norte de Santander Province, tearing off sections of roofing and shattering windows. Eleven police officers and three civilians were hurt in the explosion, according to the latest official toll. The attack happened before dawn in Cucuta, a city that sits directly on Colombia's border with Venezuela and has spent decades as a contested corridor for drug traffickers and armed groups moving people and product across that border.

Colombia's government has blamed the National Liberation Army, known by its Spanish acronym ELN, the country's largest remaining active guerrilla group, for the bombing. Defence Minister Pedro Sanchez announced a reward of roughly $60,000 for information leading to those responsible. No group had claimed responsibility as of the latest reporting.

The timing is what gives the attack its edge. Abelardo de la Espriella, the right-wing lawyer and businessman who won Colombia's presidency, is due to be sworn in on August 7, succeeding Gustavo Petro, the country's first leftist president. De la Espriella condemned the bombing directly, calling it "an atrocious, violent act." His inauguration was already shaping up as a tense handover given the political distance between his government and Petro's outgoing administration; a bombing targeting police just days beforehand adds a security dimension that Colombian authorities will now have to account for in planning the transition.

Cucuta has seen this kind of violence before. Norte de Santander has remained one of the most active conflict zones in Colombia even as the broader country has moved further from the armed conflict that defined much of its recent history, largely because the border with Venezuela remains a valuable smuggling route that the ELN and other armed groups continue to fight over. Saturday's bombing fits a pattern of attacks on security infrastructure in the region rather than marking a clear break from it.

What happens next depends largely on whether Colombian authorities can identify and locate whoever built and placed the bomb before de la Espriella's inauguration next week. For now, the province's police are working out of a damaged headquarters, and the reward for information is still on the table.