Pro-Kremlin separatist officials in Ukraine’s Kherson region announced on Tuesday they will hold a referendum this week to become part of Russia.

The leaders called on Moscow to endorse the referendum results immediately, according to Vladimir Saldo, the Russian-appointed leader of Kherson.

Saldo said in a Telegram post that he was hopeful Kherson would vote to be "a part of Russia, a fully-fledged subject of a united country.”

Russian news agencies stated that the referendum would occur between September 23 and 27, and would be similar to other votes in regions of Ukraine occupied by Russian troops, Reuters reported.

Officials in several other regions of Ukraine occupied by Russian troops, including Donetsk and Luhansk, have also announced plans for referendums on joining Russia, which may take place this week.

Russian-backed separatists in Luhansk said their vote will take place concurrently with the vote in Kherson, amid reports that Ukraine has begun recapturing strategically important areas of the breakaway region.

Saldo described Kherson becoming part of Russia as a "triumph of historical justice.”

"I am sure that the Russian leadership will accept the results of the referendum," he said.

In response to Saldo’s announcement, the speaker of Russia’s state Duma, Vyacheslav Volodin, called for Moscow back the results of the votes.

"Today, we need to support the republics with which we have signed mutual assistance agreements," he said.