Speaking to reporters after receiving a COVID-19 booster shot, the US president said Russia would be making a “serious mistake” if it used a tactical nuclear weapon.

“I’m not guaranteeing you that it’s a false flag operation yet. Don’t know. But it would be a serious, serious mistake”, - said Joe Biden.

His comments came after Russia accused Ukraine of getting ready to use a “dirty bomb” on its territory, an accusation that President Volodomyr Zelensky has rejected. “If Russia calls and says that Ukraine is allegedly preparing something, it means one thing: Russia has already prepared all this”, - Zelensky said in a video address. Moscow has said it would take its case to the United Nations Security Council, where it distributed a letter outlining its allegation.