Karachi ? An ethnic rebel group claimed responsibility for a car bombing Tuesday in downtown Karachi that hit a KFC restaurant and rattled the offices of a state-run petroleum company, killing at least three people.

Police were investigating the claim made by the Baluchistan Liberation Army, which is demanding more revenues for gas extracted from its impoverished corner of southwestern Pakistan.

The blast marked the first time the group has claimed responsibility for an attack outside Baluchistan, where it has launched occasional bomb and rocket attacks against security forces and gas pipelines.

The bomb, concealed in a stolen car parked outside the KFC, went off Tuesday morning as commuters were heading into downtown Karachi, Pakistan’s business hub and largest city. In addition to the three people killed, 22 were injured.