At least 22 Shia pilgrims returning from Iran were killed and 20 others wounded when a bomb hit a bus in the southwest Pakistan province of Baluchistan.
The attack took place at Dringhar village on the Pakistan-Iran highway some 60km west of Quetta, Baluchistan's capital.
"At least 22 people were killed and 20 others were wounded," local government official Shafqat Shahwani said.
He said 51 passengers had been on board at the time of the blast and that nine passengers were still unaccounted for due to the extent of carnage caused.
Provincial home secretary Asad Gilani said it was not immediately clear what type of bomb was used or whether it was a suicide attack.
He said that two buses had been travelling together with security vehicles provided by the government and that the bomb struck one of the buses.
Two people were killed in a similar attack on 1 January when a bomb targeted a bus carrying Shia pilgrims.
Nobody claimed responsibility for that attack but there has been a rise in sectarian violence in Pakistan after several deadly clashes between Sunni and Shia Muslim groups near Islamabad in November last year.
Shias make up around 20% of Pakistan's population, which is largely Sunni Muslim.
Oil and gas-rich Baluchistan has been badly hit by a decade-long Baluch separatist insurgency and sectarian violence, mainly targeting Shia Muslims from the Hazara ethnic community.