President Biden's National Security Adviser Jake Sullivan spoke with Secretary of the National Security Council Nikolai Patrushev and warned him against "any possible decision by Russia to use chemical or biological weapons against Ukraine."
This is noted in a statement by the White House, according to The New York Times.
The unequivocal warning came as a result of growing fears in Washington that the Russians, who failed to quickly seize Ukraine, might resort to weapons of mass destruction.
According to The New York Times, President Biden's administration separately sent a warning against the use of nuclear weapons through other channels in the early days of the war, when Vladimir Putin announced that Russian nuclear forces were on high alert.
The White House statement also said that Jake Sullivan "made clear the commitment of the United States to continue to impose sanctions on Russia, to support the defense of Ukraine's sovereignty and territorial integrity," and to strengthen defenses along NATO's eastern borders.
"Mr. Sullivan told General Patrushev that Moscow should stop attacking Ukrainian cities if Russia is serious about diplomacy," the report said.
Jake Sullivan's conversation was held hours after Secretary of State Anthony Blinken first publicly described the standard the Biden administration would use to decide whether to lift economic sanctions against Russia. According to him, the sanctions will only be cancelled when Russia completely leaves Ukraine, this must be "effectively irreversible" so that the invasion "cannot happen again" in a few years.
Earlier, Russia accused Ukraine of developing chemical and biological weapons with US assistance. In particular, Russian Foreign Minister Sergei Lavrov said that such weapons are ethnically oriented and aimed exclusively at Russians.
In turn, Ukraine claimed that Russian fake news about chemical and biological weapons in Ukraine may indicate that Putin is preparing another provocation using such weapons.