At least 41 people were killed and 20 others injured when unidentified gunmen opened fire at a bus in Pakistan's Karachi city on Wednesday.
The incident took place near the city's Safoora Chowk area, Dawn online reported.
A hospital official said the victims included 16 women.
An eyewitness said eight men riding motorcycles opened fire at the bus.
However, video footage of the bus does not show bullet holes on the body of the vehicle suggesting that the attackers may have entered and fired.
A rescue official said that at least 50 to 60 people were travelling on the bus when the attack took place.
The assailants managed to escape from the scene after the incident.
The condition of several wounded was reported as critical and the death-toll was expected to increase, the hospital official said.
