At least five persons were killed and nearly 50 others injured when a powerful explosion ripped through a bus outside a railway station in the southern Pakistani port city of Karachi on Saturday, witnesses and officials said.
Witnesses said the incident occurred at a spot located less than a kilometre from Army House, the official residence of the Pakistan Army chief when he visits Karachi.
The bus had just left a terminal near the Cantonment Railway Station when the blast went off.
Witnesses told TV news channels that they had seen body parts lying at the site.
One man told reporters a young boy was torn in two by the explosion.
Five persons were killed, said Sagheer Ahmed, the Health Minister of Sindh province.
Officials at Jinnah Hospital said they had received 48 injured people and eight of them were serious.
Women and children were among the injured.
The explosion hit several nearby shops, buildings, motorcycles and cars.
A fire erupted in the bus, which was reduced to a heap of mangled and blackened metal.
Ambulances rushed the injured to nearby hospitals.
Footage on television showed the bus on fire as a thick column of smoke rose into the sky.
Several police officials claimed soon after the incident that the blast was caused by the CNG cylinders of the bus.
However, the cleaner of the bus told the media that the vehicle ran on diesel and had no CNG cylinders.
No group claimed responsibility for the blast. Security forces cordoned off area soon after the explosion.