Russian President Vladimir Putin has said the threat of a nuclear war was rising, but insisted Russia had not "gone mad" and would not use its nuclear weapons first.
The Russian president says his country would only use weapons of mass destruction in response to an attack.
Speaking at Russia's annual human rights council meeting, he also said the war in Ukraine could be a "lengthy process".
Western officials believe Putin initially planned for a rapid victory.
Russia's capacity to use nuclear weapons has come under increased scrutiny since it invaded Ukraine in February.
Putin warned that such a threat is growing, while speaking on the prospect of nuclear war via video link from Moscow.
But he asserted that Russia would under no circumstances use the weapons first, and would not threaten anyone with its nuclear arsenal.
