Pro-Russian activists in eastern Ukraine are to go ahead with an independence referendum on Sunday, despite a call from Russian President Vladimir Putin to postpone it.
The move was announced by separatist leaders on Friday after consulting supporters. Millions of ballot papers have already been prepared for the referendum.
This week, Mr Putin called for a postponement to create the conditions necessary for dialogue.
Ukrainian authorities have said they will disregard the results and that "anti-terror" operations will continue.
The question put to voters in one region is: "Do you support the act of proclamation of independent sovereignty for the Donetsk People's Republic?''
The decision to press ahead with the vote was announced by separatist leaders in the regions of Donetsk and Luhansk.
The leader in Donetsk, Denis Pushilin, said the decision had been unanimous.
A spokesperson for the Kremlin said there was "little information" and that it needed to analyse the situation further.
The BBC's correspondent in Moscow says Mr Putin may turn the separatists' decision to his advantage, claiming it is proof that Russia is not orchestrating events in eastern Ukraine - as claimed by the West.
Moscow has vowed to protect the rights of Ukraine's Russian-speaking population against what it calls an undemocratic government in Kiev.
Ukrainian authorities have rejected activist demands for greater autonomy and troops have been battling to regain official buildings occupied by rebels in the east.
The European Union weighed in on Thursday, warning that "such a vote could have no democratic legitimacy and would only further worsen the situation".
The separatists' decision to hold the referendum comes as a Pew Research Center poll released on Thursday shows that a strong majority of Ukrainians want their country to remain unified, even in the largely Russian-speaking east.