All around the world. Im paula newton, and this is cnn newsroom. Iran is accusing israel of carrying out an assassination of its top scientist and vowing, quote, severe revenge. President hassani told the cabinet that iran will respond in time and irans Supreme Leader promised retaliation. So far, israel, has been silenced about the ambushed killing of the mastermind of the government. Cnns Nick Paton Walsh explains. Reporter the scientist lived largely in the silence. Gunned down friday in an apparent assassination according to state media. He was travel in the city east of tehran, when reports say his car was targeted by gunfire and a vehicle explosion. Irans Defense Ministry says he and his bodyguards were gravely wounded, succumbing to their injuries at the hospital a short time later. Believed to be 59, hes said to have headed the research of new technology in the countrys elite revolutionary guards. Israel Intelligence Services say he was the mastermind behind project ahmad, a de