Following twin attacks in Tehran on Wednesday that killed at least twelve people, the deputy head of Iran's Revolutionary Guards promised retaliation on Islamic State - the militant group that claimed responsibility - and its allies. "Let there be no doubt that we will take revenge for today's attacks in Tehran, on terrorists, their affiliates and their supporters," Brigadier General Hossein Salami was quoted as saying by state media. The Revolutionary Guards also said in a statement published on state media that it "has proved in the past that it will take revenge for all innocent blood shed" in Iran.