At least 4,000 Sudanese soldiers have been killed in Yemen since 2015 as part of the the Saudi-led coalition fighting against the Houthi rebels, a Houthi rebels spokesman said Saturday.

"The coalition pushes Sudanese soldiers to the frontlines in Yemen, where they come face to face with our forces," Yahya Sarea said in a press conference aired by Houthi-owned television al-Masirah.

"Our forces have captured hundreds of Sudanese soldiers during battles," Sarea noted, as al-Masirah broadcast footage showing a long line of what the Yemeni rebels said were captured Sudanese soldiers.

There was no immediate confirmation from the coalition or the Sudanese government on the Yemeni rebels' claims.

Sudan sent hundreds of ground troops to Yemen in 2015 to reinforce the Arab coalition fighting the Iran-allied Houthi group.

The Saudi-led Arab coalition intervened in Yemen's civil war in March 2015 at the request of Yemeni President Abd-Rabbu Mansour Hadi after the Houthi rebels forced him into exile.

The war has killed tens of thousands of people and pushed over 20 million Yemenis to the brink of famine, according to UN aid agencies.

Martin Griffiths, UN special envoy to Yemen, has been shuttling between Yemen's capital Sanaa and the Saudi capital Riyadh to try to rescue a peace deal reached between Yemeni warring parties in Stockholm in 2018.