In Iran, 35 people including senior commanders of Revolutionary Guards have been killed and 28 other people injured in a suicide attack in southeastern province of Sistan-Baluchestan in morning of Sunday. According to Iranian channel Press TV, Pakistan-based terrorist group, Jundallah has claimed the responsibility for the attack that targeted a unity gathering between Sunni and Shia tribal leaders in the borderline Pishin region, near the city of Sarbaz. The attacker set off his explosives belt as the meeting got underway around 8.00 am (1000 IST) in front of a gymnasium in the city of Pisheen, near the border with Pakistan. Several top regional security officials including provincial commanders of the Islamic Revolution Guards Corps (IRGC) including Brigadier Nour-Ali Shoushtari and Brigadier Rajab-Ali Mohammadzadeh were also killed in the explosion. The explosion also claimed the lives of a group of tribal leaders and well known local figures of both the Shia and Sunni communities. It was the biggest strike in recent years on the Revolutionary Guards. Sistan-Baluchestan is home to a sizeable Baluch minority and separatist Jundallah organisation, is accused of launching regular attacks in the province, which borders both Afghanistan and Pakistan.In a related development Iran has summoned Islamabad's envoy to Tehran over deadly bombing against the nation's Revolutionary Guards. Iran claimed that those behind the attack had used Pakistani soil as a springboard, the ISNA news agency said. According to it, the foreign ministry had called Pakistan's envoy and expressed Tehran's regret.The ministry also protested against the use of Pakistani territory by the terrorists and rebels against Iran. It urged Pakistani authorities to act firmly to prevent the movement of those terrorists and rebels in their country.