Colombian authorities say three bombs exploded almost simultaneously in the coastal city of Barranquilla, killing one person and injuring at least 20 others.

Investigators say two of the devices exploded Tuesday in two supermarket stores in Barranquilla. They also say the third blast happened at a local shopping center.

No one has claimed responsibility, but authorities tell the Reuters news agency the incidents could have been part of a guerrilla extortion campaign.

Colombia is mired in a long-running civil war that involves leftist rebels, rightist paramilitaries and the government. The conflict leaves thousands of people dead each year.