The UN Security Council is to vote on a resolution imposing an arms embargo on Yemen’s Houthi rebels and their allies, as they fight government supporters who are backed by Saudi-led air strikes.
The draft resolution also says the rebel force must withdraw from territory it has seized and imposes sanctions on its leadership.
But Russia, which argued for an embargo on all sides, may veto the resolution.
Iran has been accused by the Saudis of backing the rebels.
The resolution would be the first formal measure to be voted on in the Security Council since Saudi Arabia and its Gulf Arab allies began an air campaign against the rebels last month.
The Houthi rebels have seized control of much of the country, and are fighting street battles with government supporters in the port city of Aden.
The conflict has prompted warnings of a humanitarian crisis, with aid agencies saying Yemenis are fast running out of food, fuel and medical supplies.
The UN estimates more than 600 people have died and 2,000 have been hurt since the fighting intensified last month.
The draft resolution at the UN imposes an asset freeze and travel ban on the Houthi leader, Abdul Malik al-Houthi, as well as on Ahmed Saleh, the son of the former Yemeni President, Ali Abdullah Saleh.
Military units loyal to the former president are fighting alongside the Houthi rebels. Mr Saleh and several Houthi commanders are already the subject of sanctions, imposed by the UN last November.
The new draft resolution also demands the Houthis withdraw from the capital, Sanaa, and other areas recently seized.
In earlier negotiations, Russia said any arms embargo must apply to all sides in the conflict – not just the Houthis.
Russia had also reportedly argued for a “humanitarian pause” in the air campaign that would allow the delivery of aid and the evacuation of foreigners – but this text was dropped from the final draft.
Yemen has been in chaos since Houthi rebels took full control of Sanaa in January and placed current President Abdrabbuh Mansour Hadi under house arrest.
Mr Hadi escaped and took refuge in Aden in February, but left the country at the end of March when the Houthis reached the outskirts of the southern port city.
Saudi Arabia began air strikes last month against the Houthis, a Zaidi Shia rebel movement. Iran denies giving military aid to the rebels.
The US last week said it would speed up arms deliveries to the coalition fighting the Houthis.
Houthis – The Zaidi Shia Muslim rebels from the north overran Sanaa last year and then expanded their control. They want to replace Mr Hadi, whose government they say is corrupt. The US alleges Iran is providing military assistance to the rebels.
Ali Abdullah Saleh – Military units loyal to the former president – forced to hand over power in 2011 after mass protests – are fighting alongside the Houthis.
Abdrabbuh Mansour Hadi – The president fled abroad in March as the rebels advanced on Aden, where he had taken refuge in February. Sunni Muslim tribesmen and Southern separatists have formed militia to fight the rebels.
Saudi-led coalition – A US-backed coalition of nine, mostly Sunni Arab states says it is seeking to “defend the legitimate government” of Mr Hadi.
Al-Qaeda in the Arabian Peninsula – AQAP opposes both the Houthis and President Hadi. A rival affiliate of Islamic State has also recently emerged.