US National Security Advisor Jake Sullivan
US National Security Advisor Jake SullivanREUTERS/Leah Millis

US National Security Adviser Jake Sullivan has engaged in recent months in confidential conversations with top aides to Russian President Vladimir Putin in an effort to reduce the risk of a broader conflict over Ukraine and warn Moscow against using nuclear or other weapons of mass destruction, US and allied officials told The Wall Street Journal on Sunday.

The officials said that Sullivan has been in contact with Yuri Ushakov, a foreign policy adviser to Putin. Sullivan also has spoken with his direct counterpart in the Russian government, Nikolai Patrushev, the officials added.

The aim has been to guard against the risk of escalation and keep communications channels open, and not to discuss a settlement of the war in Ukraine, the officials told The Wall Street Journal.

Asked whether Sullivan has engaged in undisclosed conversations with Ushakov or Patrushev, National Security Council spokeswoman Adrienne Watson said: “People claim a lot of things” and declined to comment further. The Kremlin didn’t respond to a request for comment.

The report on the contacts comes amid tensions with Russia, after Putin issued a thinly veiled threat to use nuclear weapons, in a recent speech in which he also announced his country's first wartime military mobilization since World War Two.

President Joe Biden, in his speech at the United Nations General Assembly, accused Putin of making "overt nuclear threats against Europe" in reckless disregard for nuclear nonproliferation responsibilities.

Sullivan later said that Washington takes Putin's nuclear threats seriously but does not presently see indications of the use of nuclear weapons by Russia.