Gunmen on motorcycles boarded a bus and opened fire on commuters in Pakistan's volatile southern city of Karachi on Wednesday, killing at least 43, police said.
The pink bus was pockmarked with bullet holes and blood saturated the seats and dripped out of the doors on to the concrete.
"As the gunmen climbed on to the bus, one of them shouted, 'Kill them all!' Then they started indiscriminately firing at everyone they saw," a wounded woman told a television channel by phone.
Police Superintendent Najib Khan told Reuters there were six gunmen and that all the passengers were Ismailis, a minority Shi'ite Muslim sect. Pakistan is mostly Sunni.
Militant group Jundullah, which has attacked Muslim minorities before, claimed responsibility. The group has links with the Pakistani Taliban and pledged allegiance to Islamic State in November.
Prime Minister Nawaz Sharif said he was saddened by the attack.
"This is a very patriotic and peaceful people who have always worked for the wellbeing of Pakistan," he said. "This is an attempt to spread divisions in the country."