Iran and Saudi Arabia: rivals seeking to restore ties

After being at daggers drawn for years, longtime Middle East rivals Iran and Saudi Arabia are engaged in whirlwind diplomacy as they prepare to normalise relations after a seven-year split.

As Iran's President Ebrahim Raisi prepares to visit Saudi Arabia, AFP looks back at key moments in the relationship:

- 1979: Iran revolution -

When Iranian revolutionaries overthrow the US-backed shah in 1979 and form an Islamic republic, Sunni-led governments in the region accuse the Shiite state of seeking to "export" its revolution.

In 1980, Saddam Hussein's secular but Sunni-dominated regime in Iraq attacks neighbouring Iran, triggering an eight-year war in which oil-rich Saudi, a key US ally, supports Baghdad.

- 1987: ties cut -

In July 1987, Saudi security forces in Mecca -- the holiest site in Islam -- crack down on an anti-US protest by Iranian pilgrims. More than 400 people are killed.

Demonstrators ransack the Saudi embassy in Tehran and, in April 1988, Riyadh breaks off diplomatic relations for several years.

- 2011-2015: proxy wars in Syria, Yemen -

From 2011 on, Iran and Saudi back opposing sides in Syria's civil war.

Tehran supports President Bashar al-Assad with military forces and funds, whereas Riyadh backs Sunni rebels but also joins a US-led coalition to fight Sunni extremists from the Islamic State group.

Saudi Arabia and Iran also take opposing sides in the Yemen war.

In 2015, a Saudi-led coalition launches a seven-year campaign of air strikes against the Iran-backed Huthi rebels who seized the capital Sanaa.

- 2016: ties cut again -

In January 2016, Saudi Arabia executes prominent Shiite cleric Nimr al-Nimr, a driving force behind anti-government protests, on "terrorism" charges.

Protesters attack Saudi diplomatic missions in Iran, and Riyadh again severs ties.

In November 2017, Saudi-backed Lebanese Prime Minister Saad Hariri announces his resignation, citing Iran's "grip" on his country through the Shiite militant group Hezbollah.

Saudi Arabia is widely suspected of forcing his resignation, which he later recants.

- 2017: Qatar blockade -

In June 2017, Saudi Arabia and its allies sever ties with the tiny gas-rich Gulf monarchy of Qatar and impose a blockade on it, accusing Doha of being too close to Iran and backing extremism.

Under US pressure, Riyadh ends the embargo three years later.

- 2023: restoring relations -

In a surprise move, on March 10, 2023, Tehran and Riyadh announce Chinese-brokered plans to resume ties after seven years.

Days later, Iranian President Ebrahim Raisi receives an invitation from Saudi Arabia's King Salman to visit.

On April 6, the Iranian and Saudi foreign ministers hold talks in Beijing, where they pledge to work together to bring "security and stability" to the Middle East.

On April 9, a Saudi delegation visits the Yemeni capital Sanaa to negotiate a new truce between the ousted government and Huthi rebels, raising hopes of a possible end to the war.

- April 9-12: Syria push -

On April 9 and 12, Saudi and Iranian delegations visit each others' capitals to discuss reopening their respective diplomatic missions.

On April 12, Syria's foreign minister visits Saudi Arabia for the first high-level talks between Riyadh and the Iran-backed Syrian regime since the Syrian war started.

The aim of the visit is to "achieve a complete political settlement" to the Syrian crisis and to "bring back Syria to its Arab fold," the Saudi foreign ministry says.