Russian-appointed authorities in the southern Ukraine city of Kherson announced plans Wednesday to seek annexation – and the Ukraine response was that those officials might as well ask to join ”Mars or Jupiter.”

Kirill Stremousov, deputy head of the Russian regional military-civilian administration, also said that, by the end of May, a bank for converting money to Russian rubles will start operating in the region and ultimately will be integrated into the Bank of Russia. He said there were no plans to create a separate republic such as those sought in the eastern Donbas region.

“There will be no referendums,” Stremousov said of the annexation. “It will be a decree based on an appeal from the Kherson regional leadership to the Russian president.”

Kremlin spokesman Dmitry Peskov said that it would be “up to the residents of the Kherson region” to make such a request, which would be closely evaluated by experts to make sure its legal basis is “absolutely clear.”

Kherson, a Black Sea port city of almost 300,000, is one of a few major Ukraine cities to be under Russian control. Ukraine presidential adviser Mykhailo Podoliak dismissed the annexation plan.

“The invaders may ask to join even Mars or Jupiter,” he tweeted. “The Ukrainian army will liberate Kherson, no matter what games with words they play.”

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Latest developments:

►United Nations Secretary General Antonio Guterres said he does not see the possibility of an immediate peace deal in Ukraine. Guterres, speaking after a meeting with Austrian President Alexander Van der Bellen, suggested countries concentrate diplomatic efforts on providing humanitarian aid.

►Czech President Milos Zeman has approved a request of the first 103 Czechs to join Ukraine’s armed forces. Czech citizens are banned from service in foreign armies, but about 400 Czechs have applied for an exemption. The rest of the requests are still being processed, the government said.

►British Prime Minister Boris Johnson, visiting Sweden, pledged his country’s support should Sweden or Finland come under attack. Both nations are expected to announce this week whether they will seek membership in NATO.