No one immediately claimed responsibility for what appeared to be the deadliest militant attack to target Iran since its 1979 Islamic Revolution. Iranian state television and officials described the attacks as bombings, without immediately giving clear details of what happened. While Israel has carried out attacks in Iran over its nuclear program, it has conducted targeted assassinations, not mass casualty bombings. Until Wednesday, the deadliest attack to strike Iran since the revolution was the 1981 truck bombing of the Islamic Republican Party’s headquarters in Tehran. That attack killed at least 72 people, including the party’s leader, four government ministers, eight deputy ministers and 23 parliament members.