Burns' phone call with Naryshkin, the head of Russia's SVR foreign intelligence service, took place this week and was the highest-level contact between the two governments since the attempted mutiny, the Wall Street Journal said.

The boss of Russia's Wagner mercenary group, Yevgeny Prigozhin, shocked the world by leading last week's armed revolt, only to abruptly call it off as his fighters approached Moscow.

President Joe Biden said on Monday the brief uprising by Russian mercenaries against the Kremlin was part of a struggle within the Russian system and that the United States and its allies were not involved in it.

(Reporting by Kanishka Singh in Washington; editing by Jasper Ward)