At least 10 people were killed and dozens more wounded when a powerful bomb exploded in a passenger bus in Pakistan's southwestern Baluchistan province, local officials say.
Monday's explosion came as night fell and people working in central Quetta left for their homes on the outskirts of the city.
"I can confirm that at least 10 people have been killed and 23 were injured in a bomb explosion in a bus," Akbar Hussain Durrani, home secretary of Baluchistan province, told AFP.
A senior police official and a hospital doctor confirmed the casualties.
Durrani said the bus was loaded with labourers, but could not give any further details on how the explosion was detonated.
"We suspect somebody had hid a bomb in the backside of the bus, but there are also chances that somebody was maybe carrying it," Durrani said.
Senior police official Waheed Khatak told AFP the bomb exploded as the bus was driving near a fly-over in the Sariab road neighbourhood outside Quetta.
Doctor Noor Baluch, a police surgeon, said all 10 people were already dead by the time their bodies arrived in hospital, while 23 others had been wounded.
"Five of the injured people are in critical condition," he said.
Pakistan's southwestern Baluchistan province, of which Quetta is capital, is rife with Islamic, sectarian and separatist insurgencies.
The mineral-rich province has long been targeted by militants, and has been the scene of several attacks against the Hazara Shia community in previous years.
Before now, there had been a lull this year following a clampdown by security forces.