The Wall Street Journal has written that US President Joe Biden’s ''top national-security adviser 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 said.'' 

''Sullivan has also spoken with his direct counterpart in the Russian government, Nikolai Patrushev, the officials added.''