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 would take measures to confront what it considered such highly dangerous actions, it warned. 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 also said the ultimatum for the withdrawal of the UAE's forces had no legal basis, and insisted it would remain a main partner in the battle against the Iran-backed Houthi movement.

Earlier on Monday, the head of the eight-member presidential council, which includes STC representatives, announced that he was cancelling a joint defense pact with the UAE and ordering its forces to leave. Rashad al-Alimi declared a state of emergency for a period of 90 days. This announcement followed a coalition claim of carrying out a limited air strike on weapons and military vehicles for the STC's forces in Mukalla.

Yemen's civil war, escalating since 2014, has left over 150,000 dead and prompted a dire humanitarian crisis. The STC and other separatists have turned against the government in recent years, asserting control in the south. Tensions remain high as the situation in Yemen continues to develop.