Billionaire U.S. businessman Elon Musk proposed a plan on Twitter to end the war in Ukraine and Ukrainian officials are not taking it well, with one telling him to “fuck off.”

In a tweet on Monday, the Tesla and SpaceX CEO proposed throwing out the results of the recent referendums eastern Ukrainian territories held to leave Ukraine and join Russia.

Musk’s proposed a new referendum be held, this time under the supervision of the United Nations, and with a Russian commitment to pull out of Ukraine if the eastern Ukrainian people don’t vote to join Russia.

On Monday, the Tesla and SpaceX CEO, tweeted, “Ukraine-Russia Peace:

Redo elections of annexed regions under UN supervision. Russia leaves if that is will of the people. – Crimea formally part of Russia, as it has been since 1783 (until Khrushchev’s mistake). – Water supply to Crimea assured. – Ukraine remains neutral.” Musk shared the proposal as a yes/no Twitter poll.