Five years later, on 17 September 1980, Iraq abrogated the Algiers Agreement after Iran shelled a number of border posts on September 4 following the 1979 Iranian Revolution, which overthrew the Shah and established an Islamic theocracy. Iraqi President Saddam Hussein claimed that the newly-established Islamic Republic of Iran had refused to abide by the stipulations of the Algiers Accords and, therefore, Iraq considered them null and void. Tensions began to run high between the two states as Iraq's ruling Ba'ath party feared that Ayatollah Ruhollah Khomeini was attempting to export the Iranian Revolution to Iraq by inciting its Shia-majority population into revolting against the Secular- government. Five days later, the Iraqi military launched a major offensive and invaded Iran, sparking the Iran–Iraq War.