QUETTA: A roadside bomb ripped through a passenger bus carrying Shia Muslim pilgrims in southwestern Pakistan on Tuesday, killing three people and wounding about a dozen, officials said.

Earlier security sources said that four people killed by the attack but Deputy commissioner Mastung confirmed the killings of two people.

Six security personnel who were assigned to provide security to the bus also received injuries.

The blast took place in Mastung district, about 25 kilometres south of Quetta, the capital of insurgency-hit Balochistan province.

“It was a roadside bomb which targeted the bus,” senior administration officer Irfan Shah told AFP.

“The bus caught fire after the blast,” he said adding that initial reports said “at least two people were killed and about a dozen wounded”.

The injured, some of them in serious condition, have been taken to hospital in Quetta.

Officials said the bus, carrying up to 40 pilgrims, was returning from Iran after taking pilgrims to Shia holy place

No one immediately claimed responsibility for the attack.