A suicide bomber killed seven commanders of Iran's elite Revolutionary Guards and up to 42 other people on Sunday in an attack that President Mahmoud Ahmadinejad charged had been plotted from neighbouring Pakistan.
The foreign ministry called in Pakistan's charge d'affaires over the bombing, which targeted one of the Islamic republic's most prestigious institutions in a region that has been a hotbed of Sunni insurgency against the Shiite Muslim regime.
Several tribal leaders in the majority ethnic Baloch Sistan-Baluchestan province also died in the bombing which left many others wounded.
The attacker set off his explosives belt as a meeting of Guards commanders and tribal chiefs got underway around 8.00 am (1000 IST) at a gymnasium in the city of Pisheen, near the border with Pakistan, the state broadcaster said.
"The number of martyrs from the terrorist attack has reached 49... And that figure could still rise," the Mehr news agency reported.
Provincial chief coroner Abbas Amian told the official IRNA news agency that his office had received 42 bodies.
The chief prosecutor in Sistan-Baluchestan, Mohammad Marziah, said that Abdolmalek Rigi, the head of the shadowy Sunni rebel group, Jundallah (Soldiers of God) had "accepted the responsibility" for the attack.