In 1979, the Iranian Revolution took place. Following months of cross-border raids between the two countries, Saddam declared war on Iran in September 1980, initiating the Iran–Iraq War (or First Persian Gulf War). Taking advantage of the post-revolution chaos in Iran, Iraq captured some territories in southwest of Iran, but Iran recaptured all of the lost territories within two years, and for the next six years Iran was on the offensive. The war, which ended in stalemate in 1988, had cost the lives of between half a million and 1.5 million people. In 1981, Israeli aircraft bombed an Iraqi nuclear materials testing reactor at Osirak and was widely criticised at the United Nations. During the eight-year war with Iran, Saddam Hussein extensively used chemical weapons against Iranians. In the final stages of the Iran–Iraq War, the Ba'athist Iraqi regime led the Al-Anfal Campaign, a genocidal campaign that targeted Iraqi Kurds, and led to the killing of 50,000–100,000 civilians.