The devastating war raging in Yemen for the past three years is on the verge of entering another, even deadlier, stage.

On Sunday, forces loyal to the government of President Abdu Rabbu Mansour Hadi, backed by Saudi Arabia, exchanged fire in the southern Yemeni city of Aden with an armed group aligned with the Southern Transitional Council (STC), a secession movement supported by the United Arab Emirates.

Both sides in this conflict have been fighting alongside the Saudi-led coalition against the Iran-backed Houthi rebels for the past few years now.

In a statement issued on Sunday, Hadi's prime minister, Ahmed bin Dagher, accused the STC of staging a "coup". In the past few months, tensions have been growing between the Yemeni government, based in Aden, and the STC, as the latter became more vocal about its secessionist ambitions.

This latest turn of events could not only exacerbate the ongoing conflict in Yemen, leading to more destruction and loss of civilian lives but could also threaten the territorial integrity of the country.

Distinct history of the South

The growing secessionist sentiments in southern Yemen are a product of its distinct historical path as much as the current geopolitical situation in the region.

Aden was the only British colony in the entire Arabian Peninsula administered directly by the British government between 1839 and 1967. The British set up their own administrative, trade and educational institutions in the colony. The city was truly a cultural melting pot for many ethnic groups including people of Indian and Somali origins.

After the withdrawal of British troops in 1967, Aden joined the rest of the British protectorates in the south to form the People's Democratic Republic of Yemen, with the Yemeni Socialist Party (YSP) eventually taking power.

{articleGUID}

In January 1986, infighting erupted within the ranks of the YSP, leading to bloody clashes in the streets of Aden. There is no doubt that this conflict helped accelerate the unification of North and South Yemen in 1990. Ironically, the unification exacerbated Aden's political differences instead of reconciling them.

The deterioration of Aden's economic status and the violation of its citizens' political rights following the 1994 civil war led to the creation in 2007 of a mass peaceful movement known as al-Hirak al-Janoubi (the southern movement) that challenged former President Ali Abdullah Saleh's tight grip on power. After Saleh was toppled in the popular uprising of 2011, the Hirak gained momentum.

Weeks before the beginning of the Saudi-led offensive in Yemen on March 26, 2015, thousands of Hirak activists defended Aden against the advance of the Houthi-Saleh alliance. The UAE along, with other forces from the Saudi-led coalition, played a crucial role in backing southern resistance fighters in 2015.

Confrontation in Aden

Since its liberation from the Houthis, Aden has witnessed severe security challenges, economic and basic infrastructure problems, and most recently growing support for secession from the North. The city has also seen a deliberate attempt to silence activists supporting the Hadi-allied Islah Party (seen as having links to the Muslim Brotherhood), as well as some voices within the Salafi movement with a number of imams gunned down in the last several months.

In April 2017, forces loyal to President Hadi clashed with armed men supporting UAE-backed Aden Governor Aidarous al-Zubaidi at the city airport. Hadi responded to the incident by sacking the governor.

In May 2017, al-Zubaidi announced the establishment of the STC which he claimed would represent "the will of the people of the South". The fact that both Hadi and bin Dagher are southerners and Aden has been the seat of their government (Sanaa still being under Houthi control) has not been enough to curb al-Zubaidi's secessionist ambitions. In fact, there is a serious chance that the former governor is able to rally the support of the Hirak and push for a definitive secession.

Al-Zubaidi is backed by the STC's de-facto military wing known as the "Security Belt", which the UAE supplies with military equipment and financial resources.

{articleGUID}

Indeed, if this escalation of violence continues in Aden, it will undermine not just the course of the war against the Houthis, but the whole political process of the Gulf Initiative, the national dialogue, and the various United Nations Security Council resolutions emphasising the territorial integrity of Yemen.

The military response of Hadi's government to the current violence will shape the southern question during the post-war era. Quick restoration of military control over Aden and restructuring of the "Security Belt" forces under the direct command of President Hadi would increase the likelihood of Yemen remaining unified in the near future.

However, the political fate of Aden will also be greatly shaped by the political actions of the UAE. Since the outbreak of the current war, it was obvious that the UAE has focused much more on southern Yemen than the northern areas. The UAE's military and economic interests lie in the strategic location of Aden and its port near the Bab al-Mandab Strait.

Where Is Saudi Arabia?

While the Saudi government is more concerned with the security of its southern border and with Houthi attacks, its lack of clear coordination with the UAE in southern Yemen could undermine its overall war effort.

Saudi Arabia now has a responsibility to address both the Yemeni humanitarian crisis as well as its political future; it needs to take action on the southern question. With the present war quickly approaching its third anniversary, Saudi Arabia must pursue a speedy conclusion of the Yemeni crisis - including greater coordination with UAE - to bring stability and peace to Aden and the rest of the country.

To alleviate the growing political tension in Aden, Saudi Arabia may have to make some political concessions to the STC and the UAE regarding Hadi's government. However, that might embolden the STC and exacerbate the problem.

Whatever actions Riyadh chooses to undertake in the face of the current crisis, it has to recognise that in spite of legitimate political grievances, the secession of southern Yemen is unlikely to bring peace and stability to its people.

There are significant regional cleavages within southern Yemen which could gain political salience if Aden proceeds with its independence ambitions. Local identities with roots in the colonial era could re-emerge and aggressively reassert themselves. For example, the Hadramout region may not agree to be ruled again from Aden.

Additionally, the post-independence fate of South Sudan suggests that ill-conceived political separation is inherently dangerous and can lead to a major humanitarian crisis. Seven years after its independence from Sudan, South Sudan has become a tragedy rather than a model for other regions seeking independence.

It is now time to follow the dictates of logic and reason and avoid prolonging Aden's suffering. Otherwise, the current escalation of conflict within the city could open a new chapter of unprecedented violence and instability that Aden, the rest of Yemen and the Saudi-led coalition cannot afford.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial stance.