Ukraine has spent years without complying with the Budapest Memorandum's provisions, Russia's Deputy Representative on Disarmament at the UN First Committee, Konstantin Vorontsov, said on Tuesday.

"For many years, Kiev itself did not comply with the Budapest obligations," the diplomat said. Russia has not and is not threatening Ukraine with nuclear weapons, he underlined.

US President Joe Biden doubted last week that Russian President Vladimir Putin would use a tactical nuclear weapon, as Kiev pleaded for a rapid increase in Western military aid.

This came after Russian Foreign Minister Sergey Lavrov pointed out that Kiev creates risks associated with the use of weapons of mass destruction, which is also evidenced by the statement of Ukrainian President Volodymyr Zelensky about NATO's "preemptive" strikes on Russia.

Speaking at Australia's Lowy Institute via a video link, Zelensky said NATO should launch "preemptive" strikes on Russia rather than "waiting" for Russia to attack.

No indication of nuke usage

The United States is prepared to respond to any potential use of nuclear weapons by Russia, Pentagon Press Secretary Pat Ryder said. However, he underlined that Washington saw no signs from Moscow that it intended on kickstarting nuclear armageddon.

"We are completely ready, I can tell you that. We continue to monitor the situation very closely," Ryder said during a press briefing when asked about the Pentagon's readiness for nuclear action by Russia.

During an interview with CNN earlier in the month, Austin said "I don't see anything right now that would lead me to believe that he [Russian President Vladimir Putin] has made such a decision." 

Austin added said that Washington had previously passed on these concerns to Moscow via high-level channels while denying that he had any recent contacts with his Russian counterpart, Sergei Shoigu.