The US on Wednesday condemned reports of a plan to conduct elections in Ukraine's rebel strongholds of Donetsk and Lugansk, calling the polls a Russian-backed sham.
Both self-proclaimed republics have scheduled votes for November 11, according to Russian and Ukrainian media, following the murder of separatist leader Alexander Zakharchenko last month.
"The United States condemns the announcement of a plan to conduct 'elections' in the so-called 'Donetsk and Luhansk People's Republics,'" the State Department said.
"Given the continued control of these territories by the Russian Federation, genuine elections are inconceivable.
"By engineering phony procedures, Russia is once more demonstrating its disregard for international norms and is undermining efforts to achieve peace in eastern Ukraine."
It follows a similar statement by the European Union, which said the proposed votes ran contrary to the Minsk agreements brokered by France and Germany in 2015.
The election dates were announced following the killing of Zakharchenko, leader of the self-proclaimed Donetsk People's Republic, on August 31.
Zakharchenko was killed in a bombing at a Donetsk cafe becoming the four-year conflict's most prominent victim from the Moscow-backed side.
Moscow and rebel authorities have said Kiev was behind the assassination, while Ukraine links the bombing to internal feuding and Russia's desire to control the territory.
More than 10,000 people have been killed since the rebel insurgency broke out in the eastern Donetsk and Lugansk regions in April 2014 following Russia's annexation of Crimea from Ukraine.
Kiev and its Western allies accuse Russia of funneling troops and arms across the border. Moscow has denied the claims despite evidence to the contrary.