Russian military leaders discussed using nukes in Ukraine, a dire possibility that alarmed the US, report says

Russian military leaders have discussed using tactical nuclear weapons in Ukraine amid a string of battlefield setbacks, The New York Times reported. 

Senior US officials told the publication that the group of Russian military leaders had discussed how and when Russia might deploy tactical nuclear weapons in Ukraine. 

The report said that Russian President Vladimir Putin, who has ultimate authority over their deployment, was not part of the conversations, the Times reported.

The conversation has alarmed officials in the Biden administration, the report said, because they show how frustrated Russia's leaders are about the failures in Russia's military campaign, and that there may be substance behind Putin's recent threats to use nuclear weapons.