A businessman known as “Putin's chef” spoke with top officials in Damascus and Moscow before Russian mercenaries he is believed to control launched a disastrous attack on US and Kurdish forces in Syria, according to US intelligence reports.

The news comes just days after the businessman, Yevgeny Prigozhin, was indicted in the United States for allegedly running a pro-Kremlin troll factory that interfered in the 2016 election.

The February 7 attack was the first deadly clash between citizens of Russia and the United States since the Cold War and suggests that tensions in Syria could grow even as the Islamic State is pushed back. Moscow initially denied the casualties. The foreign ministry later admitted at least five Russians had been killed and several dozen wounded, but said they weren't soldiers.

Mr Prigozhin told a senior Syrian official in an intercepted communication in late January that he had received permission from a Russian minister for a “fast and strong” initiative and was waiting for a go-ahead from Damascus, according to intelligence reports seen by The Washington Post.