Police said about 70kg of explosives were used in the bombing, which occurred shortly after midnight.

Police blamed the bombing on
left-wing Farc rebels [AFP] 
Witnesses said they saw a man get out of a red pick-up truck where the bomb was planted and leave on a waiting motorcycle just before the explosion.

The dead man was the driver of a passing taxi.

"Miraculously, the death toll was not higher," Ricardo Ramos, a police sergeant, said.

The 17,000-member Farc was formed in 1964 and says it is fighting to narrow the gap between the country's rich and poor, but Colombia and the US describe it is a terrorist organisation funded by the multi-billion dollar cocaine trade.

Alvaro Uribe, the Colombian president, launched a nationwide security crackdown after he was elected in 2002 

"The Farc is making the point that it has not been defeated and that Uribe's security policies have not reduced its offensive capacity," Daniel Garcia Pena, a security analyst, said.

Officials say the group has recently stepped up its operations the Valle del Cauca department, of which Cali is the capital.

Thousands of people are killed and ten of thousands displaced every year by violence connected to Colombia's long-running internal conflict.