Yemeni STC and forces loyal to the country’s U.N.-recognized government whose deadly infighting erupted last summer in the war-torn Arab country are pulling back from a key southern city, military officials said Thursday.

The pullout, envisaged under a Saudi-brokered peace deal, began this week, the Yemeni officials told The Associated Press. They spoke on condition of anonymity in line with regulations.

The infighting that broke out in August between the secessionists and troops loyal to Yemeni President Abed Rabbo Mansour Hadi threatened their alliance in the Saudi-led coalition that has been fighting the country’s Houthi rebels since 2015.

The fighting prompted Saudi Arabia to pressure both sides to the negotiating table in Riyadh, where they signed a peace agreement in November. Among other provisions, the deal stipulates that both sides pull out from Zinjibar, the capital of southern Abyan province.

The withdrawal that’s underway is the first such pullout under the Saudi-brokered deal. On Wednesday, a Yemen-based Saudi media spokesman, Nasser Hibtar, said that both sides have also released dozens of prisoners and that a Saudi-led committee arrived in Abyan to discuss withdrawal from other key sites.

Under the peace deal, the separatists are also expected to turn in their weapons and eventually become incorporated in the government-controlled police force.

Yemen’s civil war began in 2014, when the Iran-backed Houthi rebels overran most of northern Yemen, including the capital, Sanaa, pushing out Hadi’s government. Hadi later fled to Saudi Arabia. The kingdom intervened in the conflict a year later, forming the Saudi-led alliance that has since battled the Houthis.

The conflict has killed tens of thousands of people and pushed the impoverished Yemen to the brink of famine. With the infighting between the separatists, who seek an independent southern Yemen, and Hadi’s forces, Saudi Arabia has been struggling to salvage its coalition, especially after its longtime ally the United Arab Emirates began withdrawing troops from Yemen.