On April 13, 1966, President Abdul Salam Arif died in a helicopter crash and was succeeded by his brother, General Abdul Rahman Arif. Following this unexpected death, the Iraqi government launched a last-ditch effort to defeat the Kurds. This campaign failed in May 1966, when Barzani forces thoroughly defeated the Iraqi Army at the Battle of Mount Handrin, near Rawanduz. Following the Six-Day War of 1967, the Ba'ath Party felt strong enough to retake power in 1968. Ahmed Hassan al-Bakr became president and chairman of the Revolutionary Command Council (RCC). The Ba'ath government started a campaign to end the Kurdish insurrection, which stalled in 1969. This can be partly attributed to the internal power struggle in Baghdad and also tensions with Iran. Moreover, the Soviet Union pressured the Iraqis to come to terms with Barzani. The war ended with more than 100,000 mortal casualties, with little achievements to both Kurdish rebels and the Iraqi government.