Source: Sullivan referred to himself as the source who warned Russia of the "consequences"

According to the source, it turned out that by "very high level" Sullivan meant himself.

Sullivan said earlier that Washington had privately warned Moscow "at a very high level" about the catastrophic consequences of using nuclear weapons.

In August, Russian Defense Minister Sergei Shoigu emphasized that Russia did not use and is not going to use chemical or nuclear weapons as part of a special military operation in Ukraine.