ISLAMABAD (AFP) Pakistan on Tuesday blamed a massive suicide attack in Iran on forces wanting to spoil relations between the countries and denied knowing the whereabouts of the alleged mastermind wanted by Tehran. The comments from foreign ministry came as Iran stepped up pressure on Islamabad, charging that the group accused of launching Sundays attack is based in Pakistan and urging its ally to confront the rebels. There are forces which are out to spoil our relations with Iran. But our ties are strong enough to counter these machinations, foreign ministry spokesman Abdul Basit told AFP. President Asif Ali Zardari had called his Iranian counterpart Mahmoud Ahmadinejad and assured him of Pakistans full cooperation in the fight against terrorism, Basit said. Irans official IRNA news agency said Ahmadinejad had urged Zardari to confront a Sunni rebel group which Tehran says was behind the bombing in Sistan-Baluchestan province. There is no question given the excellent relations between us that Pakistani territory be allowed to be used for terrorist acts against Iran, Basit told AFP. Iranian officials said the attack was claimed by Sunni militant rebel leader Abdolmalek Rigi, whose Jundallah (Soldiers of God) group has for years been waging war against Iran. The head of Irans elite Revolutionary Guards said Monday that Tehran will demand that Pakistan hand over Rigi. We dont know the whereabouts of Rigi, said the spokesman. As Interior Minister Rehman Malik said, Rigi is not in Pakistan, he added.