Voters are today heading to the polls in the eastern Ukraine regions of Donetsk and Luhansk to vote on separation from Ukraine.
Here is a guide to events surrounding the voting and what it could mean:
What are people voting on?
The question voters will be asked today is: "Do you support the act of self-rule of the People's Republic of Donetsk?"
There has been some confusion in the run-up to the poll as to exactly what the question means.
While some have interpreted it as a vote for more local powers, some believe it is a vote for broad autonomy within Ukraine, some for independence, and others still see it as a step towards incorporation into Russia.
Who organised it?
The poll is being organised and conducted by pro-Russian local authorities, whose recent climb to power is described by Kiev and the west as illegitimate and orchestrated by Russia.
Is the vote legitimate?
The interim Ukrainian government in Kiev refuses to recognise the poll, which has been organised on an ad-hoc basis with no clear control of authenticity of ballot papers or voter lists.
While pro-Russian local authorities have been quoted as saying they expect a 100% turnout at today's vote, some local media outlets have claimed that many voters do not intend to attend and do not even know where to do so.
So why does it matter?
Regardless of legality, the result of the poll will mark a statement of intent for the region - with a vote in favour of separation viewed as a potential step closer to civil war.
Those pushing for independence deny this, however, arguing that civil war has "already begun" and that "the referendum can put a stop to it and start a political process".
As with Crimea, it is possible that Russia would use any vote in favour of a Donetsk Republic to draw the region into its own control.
What does the rest of the world say?
The international community has been largely united in its condemnation against the vote.
The United States said the votes "will violate international law and the territorial integrity of Ukraine" while the Organization for Security and Co-operation in Europe said "the idea that free and fair voting could take place in these so-called referendums is absurd".
In a surprise move, Russian President Vladimir Putin called for this weekend's vote to be postponed, warning that tensions in Ukraine were developing into a "most unfavourable scenario".
However, Ukraine's acting prime minister Arseniy Yatsenyuk - who has criticised Mr Putin for supporting unrest in the country - described the comments as "hot air".