At least two people were killed and 18 injured when a bomb exploded on a bus in this southwestern Pakistani city on Sunday, a police officer told AFP from the scene.
"The death toll may increase," he said.
Of the 18 injured, five were seriously hurt, police said. All the injured had been taken to the Combined Military hospital in the city, they added.
Quetta, which is close to the border with Afghanistan, has seen repeated violent protests over US attacks on the neighbouring state.
No group made an immediate claim of responsibility for the attack.
Earlier Sunday, at least 16 people were killed when suspected Muslim extremists opened fire on worshippers at a church in eastern Pakistan -- Pakistan, (AFP)
