Saudi Arabia needs to know UAE 'serious' about Yemen pullback

Saudi Arabia welcomes the UAE's troop withdrawal in Yemen but tensions will remain while Abu Dhabi backs separatists there, a source close to the Saudi government told AFP on Wednesday.

Riyadh's position is "wait and see" after the UAE announced a pullout on Tuesday, under pressure over a sweeping advance by the separatist forces in Yemen's south.

Hours before the UAE's announcement, the Saudi-led coalition in Yemen bombed an alleged Emirati weapons shipment, and Riyadh endorsed a 24-hour deadline issued by Yemen's presidential council leader for UAE forces to leave.

"It's a good de-escalation step, but how will it play out?" the source told AFP on condition of anonymity, referring to the UAE withdrawal.

"Saudi wants to see if UAE will halt supporting the separatists," he added.

The UAE-backed Southern Transitional Council's forces have swept through divided Yemen's government-run areas this month, seizing much of resource-rich Hadramawt bordering Saudi Arabia and neighbouring Mahra province.

The rapid advance spells fresh upheaval for Yemen after more than a decade of war between the Saudi-led coalition and Iran-backed Houthi rebels who forced the government from the capital Sanaa in 2014.

It has also jolted Saudi peace negotiations with the Houthis and drawn simmering tensions with the UAE, Saudi's neighbour and fellow oil power, into public view.

"With the withdrawal, we will have to wait and see what that means," the source said.

"What counts is their support to the separatists... we will have to see if (the UAE) are serious," he added.

Abu Dhabi on Tuesday denied being behind the advance by the separatists, who insisted they were not about to withdraw from their newly captured territories.

The UAE joined the Saudi coalition against the Houthis in 2015 but withdrew most of its forces four years later, leaving only a limited number in Yemen.