There could be "no winners" in a nuclear war and it should "never be unleashed", Russian President Vladimir Putin said on Monday.
Mr Putin was speaking as a review of the keystone nuclear treaty opened at the UN.
He insisted that Russia remained faithful to the treaty's "letter and spirit" during an address to the Tenth Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons
Ties between Russia and the West have been unravelling since Mr Putin sent troops to pro-western Ukraine on February 24.
On Monday, the US, Britain and France rebuked Russia for "irresponsible and dangerous" talk about possibly using nuclear weapons.
Since the start of Moscow's military intervention in Ukraine, Mr Putin has made thinly veiled threats hinting at a willingness to use Russia's tactical nuclear weapons, which Moscow's military doctrine holds can be used to force an adversary to retreat.
Russian state propaganda has also argued for using nuclear weapons in the conflict.
In May, Russian editor and Nobel Peace Prize laureate Dmitry Muratov warned that the Kremlin's "propaganda warriors" were striving to make the use of nuclear weapons more palatable to the Russian public.
