At least 20 Revolutionary Guards have been killed in a suicide bomb attack in south-eastern Iran, state media say.
The bomber targeted a bus transporting personnel on the Khash-Zahedan road in Sistan-Baluchestan province, near the border with Pakistan.
Twenty Guards were also wounded in the attack, the official Irna news agency cited an informed source as saying.
The Sunni Muslim militant group, Jaish al-Adl (Army of Justice), has said it was behind the bombing.
Jaish-ul Adl took up arms in 2012 to fight for what it says are the rights of Iranian Sunnis, who complain of discrimination by the Shia establishment.
The group has carried out several attacks against Iranian security forces, mainly in Sistan-Baluchestan province.