Six people were killed in an explosion over the weekend aboard a public transit vehicle near Vista Hermosa, a city in the east-central Colombian province of Meta, a police spokesman told Efe.
The Revolutionary Armed Forces of Colombia, or FARC, guerrilla group, which operates in the area, is suspected of being behind the blast, the police spokesman said.
"Apparently, the FARC (guerrillas) who are there" staged the attack, the police spokesman said by telephone.
The attack was carried out by "terrorists," Defense Minister Juan Carlos Pinzon said.
Investigators have not ruled out anything and are looking at the possibility that the incident may have been "an attack" with "explosives inside" the vehicle, the police spokesman said.
The blast may have come from a package or it may have been caused "by a failure in the natural gas system" that powered the vehicle, which was completely destroyed, the police spokesman said.
The explosion occurred around noon Sunday as the vehicle was traveling through Campo Alegre, a rural area a few kilometers from downtown Vista Hermosa and the neighboring town of San Juan de Arama.
The guerrillas "blew up a vehicle, who knows if by accident or because they were transporting explosives, because they were trying to terrify somebody, and they murdered two children," the defense minister said.
The incident occurred while Pinzon was chairing a security meeting at the Apiay military base in Meta.
The FARC, Colombia's oldest and largest leftist guerrilla group, is on both the U.S. and EU lists of terrorist groups.
Drug trafficking, extortion and kidnapping-for-ransom are the FARC's main means of financing its operations. EFE