BOGOTA - An explosion on a bus in a commercial district of Colombia's capital Bogota killed two people and injured several more, police said on Tuesday.

It was not immediately clear if the explosion was the result of a bomb attack.

The Colombian government has been battling the leftist Revolutionary Armed Forces of Colombia for five decades but the rebel group has lost strength in recent years and they rarely carry out attacks in the capital.

"We're investigating what happened ... unfortunately two people were killed," a police force General Luis Eduardo Martinez told a local television network.

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