The comments come after U.S. President Joe Biden earlier in the week suggested the White House may soon end its ban on Ukraine using long-range weapons against Russia.

Biden met Friday at the White House with British Prime Minister Keir Starmer. The two leaders again pledged their unified support for Ukraine but stopped short of issuing any clarity on the use of long-range weapons.

Medvedev, who celebrated his 59th birthday Saturday, also said in his post that Russia already has “formal” grounds to use nuclear weapons against Ukraine after the latter sent troops into Russia’s Kursk region.

The comments come after Russian President Vladimir Putin this week told Western nations, allowing Ukraine to fire long-range missiles at Russia would equate to being at war with NATO.

Ukrainian President Volodymyr Zelensky on Friday again pleaded for permission to use Western-made weapons to strike Russia deep inside its borders, during a meeting with former U.S. Secretary of State Mike Pompeo in Kyiv.

“Thanks to the support of the United States and assistance in strengthening the international coalition, we are making progress on the battlefield. But we need permission to use long-range weapons. I hope that the U.S. political community understands this clearly and that the relevant decision will be made,” Zelenskyy said at the meeting.

Last week, a Ukrainian drone strike successfully ignited fuel tanks at a storage facility near the Russian town of Volokonovka.

At the same time, Medvedev also admitted in the post Saturday that “a nuclear conflict is really not needed by anyone. It is obvious that a nuclear response is an extremely difficult decision with irreversible consequences.”