Colombian policeman killed in attack on checkpoint
One policeman has been killed and seven others injured in an attack on a police checkpoint north of the capital Bogota.
The officer was shot dead by two assailants on motorcycles while he was on duty in the city's northern outskirts, police said.
The attackers planted explosives on the body and set them off when other officers came to investigate, they say.
Defence Minister Luis Carlos Villegas said the ELN rebel group is likely to have carried out the attack.
"The leading theory is that this incident is the heinous and irresponsible work of the National Liberation Army (ELN) to terrorise the civilian population," Mr Villegas told Caracol radio.
Power stations have in the past been attacked by the ELN, Colombia's second-largest rebel group.
But the police said the attack could also be part of a plan by criminal gangs to target police officers.
Attacks on the security forces used to be relatively common in Colombia, with the ELN and the larger Farc rebel group both fighting the state, but they have become rare.
The Farc signed a peace deal with the government in November, putting an end to more than five decades of armed conflict.
The ELN is due to start peace talks with the government in January but the group has so far refused to release a former Congressman it is holding hostage, which the government says is a prerequisite for the talks.
There are also a number of powerful criminal gangs operating in Colombia, some of which have in the past called for their members to kill police officers.
Officials said the assailants' original target may have been an electrical substation near the checkpoint in the sparsely populated area.