Two of the Middle East’s most powerful countries are facing off in Yemen. Here’s what to know

A decade after Saudi Arabia and the United Arab Emirates led a joint military campaign to curb Iran’s influence in Yemen, the two allies now find themselves pitted against each other there.

The Arab world’s most powerful nations have entered an unprecedented public spat over Yemen, a strategically located and impoverished nation with a history of unresolved conflicts. This week, Saudi Arabia struck a UAE shipment carrying combat vehicles bound for Yemen in an unprecedented military escalation before accusing Abu Dhabi of “highly dangerous” actions and endangering the kingdom’s national security.

The civil war in Yemen began in 2014 after the Iran-backed Houthi movement overran the north of the country and took over the capital Sana’a. Saudi Arabia and the UAE intervened the following year, propping up the local government and militias under a unified vision of destroying the Houthis.

But over the years, disagreements surfaced between rival Yemeni factions whose competing agendas unintendedly exposed a rift between the two Middle Eastern allies, Riyadh and Abu Dhabi.

Here’s how Yemen’s war has morphed into a proxy conflict involving erstwhile allies:

Who are the warring parties in Yemen and who backs them?

Since the Houthis seized Yemen’s capital, the country has fragmented into multiple spheres of influence, giving Iran expanded leverage on the southern flank of the Arabian Peninsula through its support for the group.

The Houthis, formally known as Ansar Allah, are a Shiite Islamist movement in the northwest of the country. In 2014, they orchestrated a swift takeover of Sana’a, with some popular backing, seizing control of the government. With sustained Iranian arms supplies and support, they emerged as Yemen’s most cohesive military and political entity, controlling most of the country’s northwestern border with Saudi Arabia, and holding critical Red Sea coastline, including access to vital maritime corridors. Over time, the Houthis evolved into one of Tehran’s most disruptive regional proxies, launching missile strikes on Saudi Arabia and as far as Israel. They endured a prolonged Saudi-led military campaign, which ultimately failed and led to the Houthis securing a de facto truce in 2022.

Yemen’s internationally recognized government, operating under the Saudi-backed Presidential Leadership Council (PLC), was established in 2022 to unify fragmented factions against the Houthis; it commands a loose coalition of regular military remnants, tribal militias, and Sunni Islamist groups in the center and south of the country. These forces hold a patchwork of strongholds, primarily in the central province of Marib, parts of Taiz, and Aden in the south. Since 2015, Saudi Arabia has conducted extensive air and naval operations, with limited ground troop deployments to prop up the government and counter the growing threat on its southern border.

The Southern Transitional Council (STC) is a UAE-backed separatist body in southern Yemen founded in 2017 to advocate for the restoration of the southern Yemeni state which ceased to exist in 1990 after the country unified. Militias aligned to the group are backed by Abu Dhabi and have played a crucial role in battles over the course of the war, including in recent weeks.

Why are Saudi Arabia and the UAE clashing over Yemen?

The two countries led the military intervention in 2015 to counter the Houthis and restore the internationally recognized government, but diverging agendas led them to support rival factions. The UAE’s backing of southern separatists seeking independence directly conflicts with Saudi Arabia’s support for a unified and stable Yemen at its border.

After years of stalled efforts to end the civil war, UAE-backed forces launched a rapid offensive in early December, seizing control of oil-rich provinces – at times from Saudi-backed forces – leading to deadly clashes. Tensions peaked this week when Saudi-led coalition airstrikes targeted a UAE shipment of vehicles at southern Yemen’s Mukalla port, accusing Abu Dhabi of endangering Saudi national security.

The UAE had since announced a withdrawal of its forces from Yemen.

“Over the past decade, the UAE acted at the request of the legitimate Yemeni government and the Kingdom of Saudi Arabia, and within the Saudi-led Coalition, making substantial sacrifices to support Yemen’s stability and security- particularly in confronting terrorist organizations that threaten civilians and the wider region. In line with its approach of urging calm and de-escalation, the UAE concluded the presence of its counterterrorism forces,” a UAE government official said in a statement.

On Friday, tensions further escalated as Saudi Arabia deployed its navy off Yemen’s coast shortly after Riyadh-backed forces launched what they called a “peaceful” ground offensive to retake areas from the UAE-backed southern separatists. Videos showed large convoys of vehicles allegedly on their way to the areas under control of southern forces.

The separatists rejected the claim that the offensive was peaceful, accused Saudi Arabia of misleading the international community and declared the battle a “north-south war.” Southern forces also accused Riyadh of launching several airstrikes on its locations. Saudi Arabia hasn’t commented on the matter.

Farea Al-Muslimi, a research fellow at London’s Chatham House think tank, said the unprecedented escalations “reflect fundamental disagreements between Riyadh and Abu Dhabi over the future political structure of Yemen and the balance of influence within it.”

“These actions mark a critical turning point, signaling a volatile and dangerous phase in Yemen’s fractured alliances,” Al-Muslimi said.

Internal divisions and civil wars driven by ideological differences have plagued modern Yemen for over a century. North Yemen gained independence from the Ottoman Empire after 1918, while South Yemen remained under British control until independence in 1967. The two states remained divided for about 23 years until unification in 1990, followed shortly by a civil war in 1994, in which southern separatists were defeated, leaving unaddressed grievances that contribute to ongoing conflicts.

Recurring conflicts have left the nation – strategically located south of Saudi Arabia with access to key maritime corridors – heavily impoverished, highly unstable, and well-armed, as regional powers vie for influence.

Amid the renewed conflict, Yemen splinters further, with the Houthis – once targeted by some of the region’s most powerful nations – viewing the divisions among their enemies as advantageous. The group, which launched missile and drone attacks on Abu Dhabi and Riyadh in the past, had endured a years-long Saudi-led coalition blockade and airstrikes.

“The Houthis are likely to view the growing rift between two of their principal adversaries with considerable advantage, observing as former coalition partners – who jointly fought and failed to defeat them – now turn against one another,” Al-Muslimi noted.

“How western governments will respond to escalating tensions between two of their most important regional partners remains uncertain, but the implications for regional stability and for Yemen’s already fragile political landscape are profound,” he added.