“This agreement will open, God willing, broader talks between Yemeni parties to reach a political solution and end the war,” Prince Mohammed said in a televised signing ceremony in Riyadh.

President Trump praised the agreement on Twitter. “A very good start!” he said. “Please all work hard to get a final deal.”

Saudi Arabia has been trying to resolve the standoff in southern Yemen to refocus the coalition’s attention on fighting the Houthis in the north.

The separatist forces, supported by Riyadh’s main coalition partner, the United Arab Emirates, are part of the Sunni Muslim alliance that intervened in Yemen in March 2015 against the Houthis, who hold Sana and most big urban centers.

But the main separatist political organization, the Southern Transitional Council, turned against the Saudi-backed government in August, seizing its interim seat in the southern port of Aden and trying to extend its reach in the south. The council advocates self-rule in the south and a say in Yemen’s future.