Russian President Vladimir Putin said his country was not threatening the world with nuclear weapons, but warned that Moscow "will use such weapons to defend its sovereignty".
He made the remarks on Friday while addressing the St. Petersburg International Economic Forum.
When asked to comment on the West's allegations about the threat of a nuclear war and a Third World War, the President said: "Where does it come from? From their own statements. Now and then irresponsible politicians would blurt out something like that, even high-ranking politicians...
"Are we supposed to stay silent? We are responding correspondingly. As soon as we respond, they would pick on our words and say: look, Russia is threatening us. We are not threatening anyone, but everyone should know what we have and what we will use to defend our sovereignty. These are obvious things."
Regarding Russia's ongoing war in Ukraine, Putin claimed that the legal side of the invasion, which Moscow calls "special military operation", fully complies with international law.
"When a territory is separated from a state, it is not necessary to ask permission from the central authorities," Ukrayinska Pravda quoted the President as saying as he recalled the ruling of the UN International Court of Justice on Kosovo.
"In this case the Republics of Donbas did not have to ask permission from the Kiev authorities. They declared their independence. In this regard, did we have the right to recognise them or not? Of course we did. We did that. We signed a mutual assistance agreement with them, and in accordance with this agreement, as well as with Article 151 of the UN Charter, we provide them with military assistance.
"Did we have the right? We did, in full compliance with the UN Charter. Whether people like it or not. We did it ourselves and set a precedent. Therefore, our actions are absolutely legitimate," he added.
While acknowledging that "military action is always a tragedy", Putin however said that the Ukraine war was a "necessary measure".
Speaking about the numerous sanctions imposed on Russia by the West in the wake of the war, the President leader they were "mad and thoughtless".
"The economic blitzkrieg against Russia had no chance of succeeding from the very beginning," the BBC quoted Putin as saying.
While saying that the restrictions were "more harmful" to those who imposed them, he claimed that the European Union could lose more than $400 billion because of its sanctions against Russia.
He said inflation was increasing across the 27-member bloc and the "real interests" of people in Europe were being sidelined.