Operation Scorch Sword was an Iranian airstrike on Iraq's Tuwaitha Nuclear Research Centre in 1980. Conducted eight days after the beginning of the Iraqi invasion of Iran, it was a surprise attack against the under-construction Osirak nuclear reactor, which was located 17 kilometres to the southeast of Baghdad and was widely perceived as a major asset for the then-ongoing Iraqi nuclear program. At dawn on 30 September, four Iranian F-4 Phantom IIs completed an aerial refueling near the Iran–Iraq border before flying into Iraqi airspace, where they deliberately climbed to a high altitude in order to be detected by Iraqi radar systems, albeit on a false course. Moments later, two of them peeled off and dropped to an extremely low altitude to avoid further detection and subsequently changed course for the Iraqi nuclear facility.