Imam Reza shrine bombing

On 20 June 1994, an explosion struck a crowded prayer hall in the women's section of the shrine of Ali al-Ridha, the eighth Shia Imam, in Mashhad, Iran. The blast occurred at 14:26 local time on Ashura, one of the holiest days in the Shia calendar, when hundreds of pilgrims and mourners had gathered at the shrine to commemorate the death of the third Imam, Husayn ibn Ali. The timing on this specific day is understood to have been intended to maximize casualties among the large crowd present.

The bombing killed at least 25 people and injured at least 70 others. Experts assessed the device as equivalent to approximately 4.5 kilograms (10 lb) of TNT. The explosion destroyed one wall and the dome of the prayer hall and shattered crystal chandeliers inside the shrine. The Independent described the attack as either "the first attack on such a holy place" or "the worst terrorist atrocity in Iran since 1981." In the aftermath, people gathered outside the mosque and at hospitals in protest.

Responsibility for the attack has never been conclusively established. A month after the bombing, a Sunni group calling itself Al-Haraka al-Islamiya al-Iraniya claimed responsibility. Despite this claim, the Iranian government continued to publicly blame the People's Mujahedin of Iran (MEK), an exiled opposition group, which condemned the attack and denied involvement. Some analysts and an anonymous US official alleged that Ramzi Yousef — a militant later convicted in connection with other international terrorist attacks — built the bomb, with MEK agents allegedly placing it inside the shrine, a link attributed in part to Yousef's Iraqi background. Raymond Tanter, who served on the United States National Security Council under President Ronald Reagan, has stated his belief that MEK was not involved and that a Pakistani militant connected to Yousef carried out the attack; a Pakistani newspaper identified this individual as a young religious radical living in the Lyari area of Karachi. Separately, according to the National Council of Resistance of Iran, Iran's then-Interior Minister Abdollah Nouri stated during a November 1999 trial that the bombing was a false-flag operation carried out by the Iranian government itself in order to place blame on the MEK. No individual has been named as charged or convicted in connection with the bombing based on available reporting.

Following the attack, Iranian authorities implemented strict security measures at the shrine, including the search of visitors before entry. The bombing also contributed to broader political unrest within Iran at the time. A 2013 stage play, "The Picture of Aziz's Event," later depicted the life of a woman en route to visit the shrine on the day of the bombing.