Iranian authorities say a car bomb blast near a bus used by the Revolutionary Guard Corps in southeastern Iran has killed at least 11 people and wounded 31 others.
The attack took place Wednesday near the city of Zahedan, the capital of Sistan-Baluchestan province, which borders both Pakistan and Afghanistan.
Earlier, Iran's state-run news agency, IRNA, said the blast killed 18 people and wounded several others. But the report did not specify how many of the victims were members of the Guards.
A local Guards commander, Qassem Rezaie, is quoted as saying "Zahedan citizens" were killed.
Witnesses say assailants riding on two motorcycles first opened fire on the bus and as the vehicle approached, they detonated the explosive-filled car parked on the side of the road. They say the assailants escaped.
Iran's semiofficial Fars news agency says a Sunni militant group that calls itself Jundollah - or God's Soldiers - has claimed responsibility for the attack.
Iran has blamed the group for killings and kidnappings in the area in the past. Tehran says the group is linked to al-Qaida.
Some information for this report was provided by AFP, AP and Reuters.