The Treasury Department sanctioned high-ranking military leader Brigadier General Qusay Mihoub of the Syrian Air Force Intelligence, saying he had ordered his unit in the southwestern city of Daraa to "stop the protesters by all possible means," including lethal force, during anti-government marches in 2011.
"Under Mihoub's command, the SAFI Daraa Branch was responsible for human rights abuses and the deaths of hundreds of civilians, including targeted assassinations," the US Treasury said.
It said officers in the unit had shot, beaten, detained, tortured and burned alive detainees.
Ioannou is suspected of helping Damascus skirt sanctions. Piruseti and Frumineti are accused of serving as front companies for the Syrian government and its financial supporters.
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Lebanon-based DK Group Sari and its general manager Jad Dagher were also designated for their material support to the Syrian regime.
The company is said to have arranged to ship Syrian pound banknotes from Russia to the Central Bank of Syria, usually via third-country cargo flights.
Four banks were listed as being owned or controlled by the Syrian government and sanctioned.
The move freezes any assets the designees may have under US jurisdiction and bars all financial and commercial transactions by any American or US-based persons with them.