Yemen’s anti-Houthi forces declared a state of emergency on Tuesday after Saudi Arabia conducted airstrikes on the port city of Mukalla. Riyadh said the strikes targeted an arms shipment meant for UAE-backed separatists. The anti-Houthi authorities also canceled their security agreement with the UAE in an official statement, saying, “The Joint Defence Agreement with the United Arab Emirates is hereby cancelled.” Following the attack, a 72-hour ban on all border crossings was put in place. Saudi Arabia stated that the airstrikes hit armored vehicles and weapons unloaded from ships that came from Fujairah in the UAE to Mukalla. The Saudi-led coalition claimed the ships had turned off their tracking systems while carrying military gear intended for the Southern Transitional Council (STC), a powerful UAE-backed separatist group. The coalition called the weapons an “imminent threat” to peace. The strikes were limited and precise to avoid civilian harm. Analysts note the attack reveals growing tensions between Saudi Arabia and the UAE, both close allies that back rival groups in Yemen's long war. Though they both oppose the Houthis, they support different factions on the battlefield. Satellite data showed at least one ship carrying weapons docked in Fujairah on December 22 before reaching Mukalla on Sunday. Mukalla is in Yemen’s Hadramout governorate, about 480 kilometers northeast of Aden, the temporary capital. The STC has been expanding in the region, pushing out Saudi-backed forces. This strike follows earlier Saudi airstrikes last Friday that warned the STC to stop its advance in Hadramout and neighboring Mahra. The separatists have increased their activity recently, with supporters flying the flag of former South Yemen, a separate state until 1990. The developments add to broader unrest in the Red Sea area, where Saudi Arabia and the UAE back opposite sides in Sudan’s conflict. Tensions also rise after Israel recognized Somalia’s Somaliland, provoking threats from Yemen’s Houthi rebels. Eastern Yemen remains unstable as these regional rivalries make peace efforts harder.