The UN Security Council will meet tomorrow to vote on a resolution on the Ukraine crisis but permanent member Russia is virtually certain to veto it.
The Luxembourg mission to the UN tweeted that the council will meet tomorrow morning. Luxembourg currently holds the council presidency.
The draft resolution urges all parties "to pursue immediately the peaceful resolution of this dispute through direct political dialogue".
It says Ukraine has not authorised Sunday's referendum in Crimea on whether to become part of Russia, and "declares that this referendum can have no validity, and cannot form the basis for any alteration of the status of Crimea".
Western powers hope that China, which usually supports Russia, will abstain rather than join Russia in vetoing the resolution.
UN Secretary-General Ban Ki-moon earlier urged Russia and Ukraine to avoid provocation and hasty decisions in the coming days, warning there is "a great risk of dangerous, downward spiral".
He said no "hasty measures" should be taken following Sunday's referendum on whether Crimea should become part of Russia that "may impact the sovereignty, unity and territorial integrity of Ukraine".
He added: "It is clear that we are at the crossroads."
He said he had spoken earlier today with Russian president Vladimir Putin and discussed "the need to work towards a durable and fair political solution".
Last night he met Ukraine's PM Arseniy Yatsenyuk and said they discussed "the need for all concerned to respect the law and for calm in an increasing complex and threatening situation".