car bomb has exploded in the centre of the Colombian port city of Buenaventura, killing at least four people

More than 20 people were hurt in the blast near the mayor's office and the local public prosecutor's building, the authorities say.There was no immediate claim of responsibility for the blast.Rebels and traffickers are active in the region which lies on a key cocaine smuggling route.
The explosion has caused widespread damage in the centre of Buenaventura, Colombia's main Pacific port, local media report.
"This is an unfortunate terrorist act," said army commander General Freddy Padilla, indicating he suspected it was the work of rebels from the Revolutionary Armed Forces of Colombia (Farc).
President Alvaro Uribe, who leaves office this August, has pursued a tough security policy against the rebels during his years in office.
They have been put on the defensive but they are still able to carry out attacks.
In recent months, the Farc has increased its raids on military posts in the region.
Buenaventura, which has easy access to the coast, has over the years seen battles between guerrilla groups, drug traffickers and paramilitaries for control of lucrative smuggling routes.
It has been hit by bomb attacks in the past.