A bomb thundered through a popular beach on Sunday, killing two, including a 2-year-old, outside a Colombian city shaken by a series of recent bombings.
Authorities said explosives were hidden in a tractor that was used to transport revelers on the beaches of Juanchaco near the Pacific Coast city of Buenaventura, Colombia's largest port and a major exit point for drugs leaving the country.
A wave of bombings across Buenaventura that authorities blame on leftist rebels left 23 people injured on Friday.
A naval spokesman who asked not to be named for security reasons said five wounded in Sunday's blast were being treated in a nearby military hospital.
The attack took place despite increased patrols over the weekend in Buenaventura, where the mayor has declared a nighttime curfew. The defense minister is coming to oversee the response by security forces.
It was not clear who was responsible for Sunday's bombing. Authorities blamed the previous bombings on rebels seeking revenge for the recent killing by the navy of a regional guerrilla commander of the Revolutionary Armed Forces of Colombia, the nation's largest rebel group.
This steaming hot Pacific Coast city of 300,000 is Colombia's most violent, with drug traffickers, leftist rebels and far-right death squads all battling for control of lucrative drug routes flowing through the port.