Senior Russian military leaders recently had conversations to discuss when and how Moscow might use a tactical nuclear weapon in Ukraine, contributing to heightened concern in Washington and allied capitals, according to multiple senior American officials.

President Vladimir Putin was not a part of the conversations, which were held against the backdrop of Russia’s intensifying nuclear rhetoric and battlefield setbacks.

But the fact that senior Russian military leaders were even having the discussions alarmed the Biden administration because it showed how frustrated Russian generals were about their failures on the ground, and suggests that Putin’s veiled threats to use nuclear weapons might not just be words.