The United States has joined the European Union in condemning plans by Russia-backed separatists in eastern Ukraine to hold "elections," calling them "phony procedures" that undermine peace efforts in the region.

"The United States condemns the announcement of a plan to conduct 'elections' in the so-called 'Donetsk and Luhansk People’s Republics,'" State Department spokeswoman Heather Nauert said in a statement on September 12.

"Given the continued control of these territories by the Russian Federation, genuine elections are inconceivable, and grossly contravene Russia's commitments under the Minsk agreements," she added, referring to September 2014 and February 2015 pacts aimed at resolving the conflict.

She said that by "engineering phony procedures," Moscow was exhibiting "its disregard for international norms and is undermining efforts to achieve peace in eastern Ukraine."

On September 8, EU foreign-policy chief Federica Mogherini also criticized the plan and called on Moscow to use its influence to stop the planned November 11 vote from taking place.

Ukraine's Foreign Ministry also decried the announcement by the separatist officials in the Donbas region.

"If fake 'early elections' are conducted, their outcome will be legally void, they will not create any legal consequences, and will not be recognized by Ukraine or the global community," the ministry said in a statement on September 7.

The separatists have vowed to hold elections to choose the region's parliament and a new leader.

Donetsk separatist leader Aleksandr Zakharchenko was assassinated by a bomb blast in a city cafe on August 31. Denis Pushilin, the chairman of the "people's council" was selected as the acting head until the November 11 vote to select a new leader.

More than 10,300 people have been killed in fighting in eastern Ukraine since April 2014 in the conflict, which erupted as Russia fomented separatism after Moscow-friendly President Viktor Yanukovych was pushed from power by huge pro-European protests in Kyiv.

Russia's actions in eastern Ukraine and its seizure and annexation of Ukraine's Crimea Peninsula led the United States and EU to impose sanctions against Moscow and has heightened tensions between Russia and the West.