Karachi:
A motorcycle bomb exploded on Tuesday near the venue of a major political rally in Pakistan's largest city Karachi, killing four people and injuring 42 others, officials said.
The bombing appeared to be targetted at buses carrying supporters of the city's dominant political party, the Muttahida Qaumi Movement (MQM), which organised the rally attended by thousands of people.
"The latest report we have collected from hospitals said that four people have been killed and 42 are injured," provincial health minister Saghir Ahmad told AFP, updating the earlier toll of two dead and 25 injured.
Another health official at Karachi's Abbasi Shaheed hospital confirmed the new toll.
"The bomb was planted in a motorcycle," said Asif Ijaz, a senior police official.
Imran Shokat, a police spokesman in the southern Sindh province of which Karachi is the capital, said the motorcycle was parked in a congested neighbourhood near the venue of the rally.
"Bomb disposal experts are investigating but preliminary reports said it was a remote-controlled bomb," Shokat told AFP.
Karachi, the commercial capital of Pakistan with an estimated population of 18 million, is in the grip of a long-running wave of political and sectarian violence.
Its Arabian Sea port is used by the United States and NATO to ship supplies to the war in neighbouring, landlocked Afghanistan.