In 1966, the original Ba'ath Party was split in half; one half was led by the Damascus leadership of the Ba'ath Party which established a party in Syria and the other half with its leadership in Baghdad. The two Ba'ath parties retained the same name and maintained parallel structures in the Arab world, but relations became so antagonistic that Syria became the only Arab state to support Iran against Iraq during the bloody Iran–Iraq War; it also joined the U.S.-led coalition against Iraq in the Gulf War. The Ba'athists seized power in Iraq for the first time in 1963, but were deposed several months later. The party's regional organisation governed Iraq between 1968 and 2003, for many years under the leadership of Saddam Hussein. The Arab Socialist Ba'ath Party – Iraq Region was banned in 2003 by the Coalition Provisional Authority following the invasion of Iraq.