Ukraine's President Volodymyr Zelensky said Russian officials have begun to "prepare their society" for the possible use of nuclear weapons.
In an interview with the BBC at the president's office in Kyiv, he denied having urged strikes on Russia, claiming that an earlier remark had been mistranslated.
He said, "You must use preventive kicks," he said, referring to sanctions, "not attacks," reports BBC.
Zelensky said, "They begin to prepare their society. That's very dangerous.
"They are not ready to do it, to use it. But they begin to communicate. They don't know whether they'll use or not use it. I think it's dangerous to even speak about it."
He, however, denied having called for strikes on Russia during an online event on Thursday, saying the Ukrainian word he had used had been misunderstood.
The interview happened hours after US President Joe Biden said that the Russian threat to use nuclear weapons had brought the world closer to "Armageddon" than at any time since the Cuban Missile Crisis during the Cold War.
Zelensky said action was needed now, as Russia's threats were a "risk for the whole world".
Bd-pratidin English/Golam Rosul