A Russian oligarch believed to control the Russian mercenaries who attacked U.S. troops and their allies in Syria this month was in close touch with Kremlin and Syrian officials in the days and weeks before and after the assault, according to U.S. intelligence reports.

In intercepted communications in late January, the oligarch, Yevgeniy Prigozhin, told a senior Syrian official that he had “secured permission” from an unspecified Russian minister to move forward with a “fast and strong” initiative that would take place in early February.

Prigozhin made headlines last week when he was indicted by Special Counsel Robert Mueller on charges of bankrolling and guiding a long-running Russian scheme to conduct “information warfare” during the 2016 U.S. presidential campaign.

He is known to have close ties to Russian President Vladimir Putin, forged when he was a restaurateur in St. Petersburg and expanded through what became Prigozhin’s wide-ranging business empire, including extensive contracts with Russia’s Defense Ministry.

Among his various enterprises, U.S. intelligence believes that Prigozhin also “almost certainly” controls Russian mercenaries fighting in Syria on behalf of President Bashar Assad. The mercenaries, employed by a company called Wagner, comprise ultranationalist Russians and military veterans, some of whom also fought in the Ukraine conflict, according to Russian news reports.

The incident took place on the night of Feb. 7-8, when a headquarters base of U.S. troops and their Syrian allies, located near a strategic oil field several miles east of the river close to the town of Deir al-Zour, was attacked by 300 to 500 “pro-regime” forces.

The Americans quickly mobilized a ferocious response, including AC-130 gunships, jet warplanes and Apache attack helicopters. After three hours, the attacking force retreated, leaving behind what the U.S. military said was about 100 dead attackers. No casualties were reported among the Americans and their allies, the Syrian Democratic Forces.