Six dead in Bogota car blast

At least six people have been killed and another 12 injured in a car bomb explosion in the Colombian capital, Bogota.

The bomb went off as police approached a suspicious car

Police chief General Jorge Dario Castro said two of those killed were police officers.

The explosion took place in a commercial area of central Bogota at about 0800 local time (1300 GMT).

It is not clear who was behind the attack.

Local residents had alerted police to a suspicious car - reportedly a jeep - parked near some shops, police said.

They said the bomb exploded when police approached the car, killing two police officers and four civilians.

There was smoke everywhere. I saw four dead people, including the woman who sells coffee here Teodora Lagos, cleaning lady

The blast shattered the windows of nearby shops, which were starting to open up for business.

"We all ran out and looked around. There was smoke everywhere," Teodora Lagos, a cleaning lady working in a nearby bank, was quoted as saying by the Associated Press news agency.

"I saw four dead people, including the woman who sells coffee here," she added.

Extortion

In the past, Colombian authorities have blamed left-wing rebel groups for carrying out similar attacks in the capital and other cities.

The BBC's Jeremy McDermott in Columbia says members of the Revolutionary Armed Forces of Colombia (FARC) will be the prime suspects.

FARC rebels have been blamed for previous Bogota attacks

In February, FARC rebels were accused of bombing an exclusive social club in Bogota, killing 36 people.

The group was also blamed for an attack on a nightclub in the city of Florencia last month, that left 12 people dead.

But our correspondent says that other groups cannot be ruled out as guerrillas, right-wing paramilitaries and criminal gangs are known to extort money from shopkeepers.

He says there is a possibility that the blast could have been punishment for the non-payment of protection money. The area is known for its informal black market, where contraband goods are sold.

Leftist guerrillas, right-wing paramilitaries and the government have been fighting each other for four decades in Colombia's bitter civil war.

In the past decade alone, more than 35,000 people are believed to have been killed in the fighting.