The war pits Iran-supported rebels against Yemen government forces backed by a Saudi-led coalition.

The conflict has left about 377,000 dead, according to the UN, either directly in the fighting or as victims of famine, sickness and a lack of clean drinking water.

- 2014: Huthis take capital -

Huthi rebels from the Zaidi Shiite minority in northern Yemen seize the capital Sanaa in September 2014.

Backed by Shiite heavyweight Iran, they ally themselves with military units loyal to ex-president Ali Abdullah Saleh, who had been forced to step down after a 2011 uprising.

They also take swathes of territory including the vital Red Sea port of Hodeida.

President Abedrabbo Mansour Hadi flees in February 2015 to second city Aden on Yemen's south coast.

- 2015: Saudis step in -

A coalition led by Iran's bitter enemy Saudi Arabia that includes the United Arab Emirates enters the conflict in March 2015 with air strikes on the rebels.

Washington says it is contributing logistics and intelligence.

As the rebels advance on Aden, Hadi flees to Saudi Arabia.

The coalition's intervention helps pro-government forces secure Aden, and in October they announce having retaken control of the Bab al-Mandab strait, one of the world's most strategic waterways.

- 2018: Battle for key port -

In June 2018, government fighters, backed by Saudi and Emirati ground forces, launch an offensive to retake Hodeida, a key entry point for humanitarian aid.

UN-brokered talks between the warring parties open in December, with a ceasefire declared in Hodeida.

But in mid-January 2021, clashes break out between rebels and pro-government soldiers in the south of the city.

- Separatists flex muscles -

The anti-Huthi camp is divided.

South Yemen was an independent state before unifying with the north in 1990, and southern separatists frequently clash with unionists loyal to Hadi's government.

The separatists occupy the presidential palace in Aden in January 2018, before Saudi and Emirati forces intervene.

In August 2019, separatists in Aden from the UAE-trained Security Belt force clash again with unionist troops.

Riyadh has since negotiated a power-sharing agreement and the formation of a new government.

- 2019: Saudi oil hit -

The rebels escalate their attacks on Saudi Arabia, using drones and missiles.

A major hit on September 14, 2019 on Abqaiq processing plant and Khurais oilfield halves the kingdom's crude output.

Riyadh and Washington accuse Iran of being behind the attack, which it denies.

- 2021: New escalation -

On February 8, 2021, the Huthis resume an offensive to seize oil-rich Marib province, the government's last northern stronghold.

The upsurge comes shortly after Washington ends its support for coalition military operations and removes the Huthis from a "terrorist" blacklist.

Fighting intensifies over the following months.

- 2022: Rebels turn on UAE -

On January 3, 2022, the rebels seize an Emirati-flagged vessel in the Red Sea, which the coalition says is carrying medical supplies.

The rebels say it was "a military cargo ship with military equipment".

A week later, pro-government forces with UAE backing claim to have retaken Shabwa province in a blow to rebel efforts to overrun neighbouring Marib.

On January 17, a rebel drone and missile attack on an oil facility in Abu Dhabi, kills two Indians and a Pakistani worker, the first deaths inside the UAE from the Yemen conflict.

The Saudi-led coalition kills 14 people in retaliatory air strikes on Sanaa.

- Deadly strike on prison -

On January 21, at least 70 people die and more than 100 are wounded in an air strike on a prison in northern Yemen.

At least three children die in a separate bombardment of Hodeida, aid group Save the Children says.