Saudi Arabia has backed a demand from Yemen's presidential council for the United Arab Emirates to withdraw within 24 hours, after a Saudi-led coalition bombed what it said was a weapons shipment for UAE-backed separatists at the port of Mukalla.

The Saudi foreign ministry accused the UAE of pressuring the Southern Transitional Council (STC), which seeks independence for southern Yemen, to launch recent offensives in the eastern provinces of Hadramawt and al-Mahra.

The kingdom warned it would take measures to confront what it considered such highly dangerous actions.

The UAE's foreign ministry denied that the shipment contained weapons and expressed deep regret at the Saudi statement. It strongly condemned the allegations that it exerted pressure on, or directed, any Yemeni party to carry out military operations that would undermine the security of the sisterly kingdom of Saudi Arabia or target its borders.

The STC's leaders stated the ultimatum for the withdrawal of UAE forces had no legal basis, insisting it remains a main partner in combating the Iran-backed Houthi movement, which controls much of north-western Yemen.

Earlier on Monday, the head of the eight-member presidential council - which includes STC representatives - announced the cancellation of a joint defense pact with the UAE and ordered its forces to leave, stressing the importance of Yemen's unity and security.

Rashad al-Alimi declared a state of emergency for 90 days, deeming it necessary to confront the Houthis and internal strife led by military elements allegedly influenced by the UAE.

The ultimatum followed the statement from the Saudi-led coalition, which included the UAE, regarding a limited air strike aimed at STC military vehicles in Mukalla, claiming it was a response to an imminent threat to stability.

Images from the aftermath revealed burned military vehicles at the port, highlighting the escalating tensions between the UAE and Saudi Arabia as they navigate their roles in Yemen's conflicted landscape.

Yemen has been embroiled in a civil war since 2014 following the Houthis' ousting of the government in Sanaa, exacerbated by the Saudi-led coalition's intervention in 2015. This conflict has resulted in over 150,000 deaths and one of the world's worst humanitarian crises.