A fire has been spreading near San Francisco since an explosion in a residential neighbourhood.

The explosion, which occurred near San Francisco’s international airport, has already destroyed a number of homes, with people fleeing the area where the explosion went off in the residential street.

The fire spread across San Bruno, a suburb just south of San Francisco, just after the blast, which officials believe was set off in a natural gas pipeline.

There had earlier been fears that a plane might have come down onto the houses.

Locals were fearful the blast, so close to the busy airport, was an act of terrorism prior to Saturday’s ninth anniversary of the September 11, 2001 attacks.

Witnesses reported hearing a loud explosion and seeing massive balls of fire.