Conflict-ravaged Yemen, scene of alleged war crimes which have just been referred to the International Criminal Court, is currently facing "the world's worst humanitarian crisis", the UN says.

The war has killed more than 8,750 people, including many civilians, since a Saudi-led military intervention in 2015, and brought the impoverished country to the brink of famine.

The conflict is underscored by the regional rivalry between Iran, a supporter of Yemen's Shiite Huthi rebels, and Saudi Arabia, which heads a coalition backing the president.

Here is an overview:

- 'Decisive Storm' -

On March 26, 2015, the coalition launches operation "Decisive Storm" with air strikes on Huthi rebels to defend embattled President Abedrabbo Mansour Hadi, who seeks shelter in Riyadh.

Later named "Restoring Hope", it aims to defeat the rebels who have controlled the capital since September 2014 in addition to large swathes of northern, central and western Yemen.

- Aden liberated -

In July 2015 the government announces the liberation of southern Aden province from rebel control after more than four months of fighting. It is their first success since the coalition stepped in.

The coalition supplements its air power with hundreds of ground troops and by mid-August loyalist forces have retaken the whole of the south.

However they face a growing presence of fighters from Sunni jihadists of Al-Qaeda and the Islamic State group.

In January 2017, pro-government troops backed by coalition planes and ships launch operation "Golden Spear" around the strategic Bab al-Mandab Strait, between the Red Sea and the Gulf of Aden.

- Carnage -

In September 2015, the coalition is accused of hitting a wedding hall in Mokha in an air strike, killing 131 people. The coalition denies responsibility.

In August 2016, it bombs the hospital in the town of Abs in the northwest of the country, the fourth strike to hit a building housing aid group Medecins sans Frontieres (Doctors without Borders) in a year.

In October 2016, a coalition air strike at a funeral ceremony in Sanaa kills 140 people and wounds more than 500, according to the UN.

On September 12, 2017, Human Rights Watch accuses the Arab coalition of having carried out five air strikes since June in which 39 civilians, including 26 children, were killed.

- Famine -

On November 4, 2017, Huthi rebels fire a missile in the direction of the international airport in Riyadh. Intercepted and destroyed, it is the first to reach the Saudi capital.

It leads Saudi Arabia to accuse Iran of "blatant military aggression" through its support of the rebels.

On November 6 the coalition shuts down Yemen's borders and halts aid deliveries in response.

Iran in turn accuses its rival of war crimes and the rebels threaten to attack ports and airports in Saudi Arabia and the United Arab Emirates.

The UN warns on November 8 that Yemen faces mass famine unless the coalition ends the blockade and allows aid deliveries to enter.

It could "be the largest famine the world has seen for many decades, with millions of victims," UN aid chief Mark Lowcock says.

On the 22nd, the coalition announces the reopening of Hodeida port and Sanaa airport, both under control of rebels. But little aid has entered through the Red Sea port, the main conduit for UN-supervised deliveries of food and medicine.

- War crimes -

In June 2017, Human Rights Watch accuses the United Arab Emirates -- a member of the Saudi-led coalition -- of operating at least two informal detention facilities in Yemen. Abu Dhabi denies the accusation.

In September, the UN Human Rights Council agrees to send war crimes investigators to Yemen.

On November 27 the Arab Organisation for Human Rights in the United Kingdom calls on the International Criminal Court to investigate allegations of war crimes in Yemen.

The London-based group accuses the UAE government of "indiscriminate attacks against civilians" and of using banned cluster bombs and hiring mercenaries to carry out torture and executions.

Source: AFP