The Iranian pilgrim riot arose on July 31, 1987 from escalating tensions between Shiite Iran and Sunni Saudi Arabia.

For years, Iranian pilgrims had tried to stage political demonstrations in the Muslim holy city of Mecca during the hajj. On July 31 1987, Iranian pilgrims tried to stage another political demostration but riot police broke it up with force. This resulted in 402 people killed (275 Iranians and 85 Saudi policemen) and 650 wounded. The Saudi government blamed the riot on the Iranian pilgrims and claimed that the Iranian pilgrim riot was part of a plot to destabilize the Saudi regime.

When news of the riot and deaths reached Iran the next day, Iranian government-organized mobs attacked the embassies of Kuwait and Saudi Arabia in Tehran, resulting in the death of a diplomat. The following day, over a million Iranians gathered in Tehran calling for the overthrow of the shaikh of Saudi Arabia.