Islamabad: The incident occurred as a suicide bomber rammed his explosive-laden vehicle into the pilgrims' bus in Dareen Ghar area of Mastung district, local media reported.

The bus was carrying over 50 pilgrims who were on their way back from Iran's Taftan city to the provincial capital Quetta in Balochistan, said Shafqat Anwar, assistant commissioner of Mastung, adding the bus caught fire following the blast causing heavy casualties.