Explosion kills four on Colombia bus

An explosion killed at least four people and injured more than 30 others in an apparent terror attack on a crowded bus in northwest Colombia, police said.

Officials are investigating whether there was a bomb inside the bus, or if explosives were placed at the roadside.

The explosion came as it travelled on a rural road outside the town of Taraza in Antioquia state, said Colonel Dagoberto Garcia, the Antioquia police commander.

It was not immediately clear who the assailants were, though Dagoberto said that leftist rebels of the Revolutionary Armed Forces of Colombia, or FARC, are fighting right-wing paramilitary groups for control of the region, which is 220 miles northwest of Bogota, the capital.

Colombia’s civil war, which pits the rebels against the government and the militia, is in its 39th year.

About 3,500 people, mainly civilians, die in the fighting each year.