The White House said that William Burns, the director of the CIA, warned Sergei Naryshkin, the head of Russia's foreign intelligence service, not to use a nuclear weapon.

The White House said that Burns did not conduct negotiations as he met with Naryshkin in Ankara, explaining that he was conveying a message on the consequences of the use of nuclear weapons by Russia.

The Biden administration will not hold official talks on Ukraine without the involvement of the Ukrainian government, according to the spokesman.

Russian President Vladimir Putin has made repeated nuclear threats since launching a full-scale invasion of Ukraine in February, sparking fears that he might follow through if the Russian leader's invasion fails to achieve its objectives.

In April, Burns warned that Putin could use a nuclear weapon if he felt like it.

No one can take lightly the threat posed by a potential resort to tactical nuclear weapons or low-yield nuclear weapons by President Putin and the Russian leadership.

Russian forces have lost ground to the Ukrainians since those remarks.

Many military analysts and nuclear experts don't think that Russia will use a nuclear weapon in Ukraine because they think it's a ploy to deter the West from continuing to offer security assistance to the country. Analysts don't think the Russian military could pull off such an attack. Russian forces have suffered a lot of losses since the war started.

There are indications that Russia's global partners would revolt against the Kremlin if it took such a drastic step.

The president met with the Chinese leader on Monday. The White House said that the two world leaders "reiterated their agreement that a nuclear war should never be fought and can never be won, and underscored their opposition to the use or threat of use of nuclear weapons inUkraine."