Yemen's government has signed a power-sharing deal with separatists in the south of the country that is intended to end months of infighting.
The two are meant to be part of an alliance with a Saudi-led multinational coalition that has been battling the rebel Houthi movement since 2015.
But in August, separatists supported by the UAE seized control the city of Aden from Saudi-backed government forces.
The UN said the deal was an important step towards ending Yemen's civil war.
The conflict has devastated the country and claimed the lives of at least 7,000 civilians, according to the UN.
Monitors believe the death toll is far higher. The US-based Armed Conflict Location and Event Data Project (ACLED) said last week that it had recorded more than 100,000 fatalities, including 12,000 civilians killed in direct attacks.
The fighting has also triggered the world's worst humanitarian crisis. Four-fifths of the population - 24 million people - are in need of humanitarian assistance or protection, including 10 million who rely on food aid to survive.
Separatists seeking independence for south Yemen, which was a separate country before unification with the north in 1990, formed an uneasy alliance with President Abdrabbuh Mansour Hadi four years ago to stop the Houthis capturing Aden.
They subsequently drove the rebels out of much of the south with the help of the Saudi-led coalition, and Aden became the temporary seat of Mr Hadi's cabinet.
But in August, the separatist Southern Transitional Council (STC) turned on the president, accusing his government of mismanagement and criticising his ties to Islamists. Following several days of deadly clashes, militia fighters aligned to the STC seized control of Aden from troops loyal to the government.
When the government tried to retake the city, the UAE intervened with air strikes.
Saudi Arabia brokered a truce before hosting talks that led to Tuesday's deal.
A copy of the agreement seen by Reuters news agency calls for the formation of a new cabinet within 30 days with equal numbers of northerners and southerners.
The STC will also be allowed to join any UN-mediated talks to end the civil war.
Fighters from both sides will be placed under the command of the defence and interior ministries, and the Saudi forces will oversee security inside Aden, according to Reuters. The UAE, which has been withdrawing troops from Yemen since July, handed over control of Aden to them last month.
"This agreement will open a new period of stability in Yemen. The kingdom of Saudi Arabia stands with you," Saudi Crown Prince Mohammed bin Salman said.
The UN's special envoy for Yemen, Martin Griffiths, said it was an "important step for our collective efforts to advance a peaceful settlement to the conflict in Yemen".
"Listening to southern stakeholders is important to the political efforts to achieve peace in the country," he added.
US President Donald Trump, who has maintained logistical and intelligence support for the Saudi-led coalition in Yemen despite strong opposition in Congress, tweeted: "A very good start! Please all work hard to get a final deal."