WASHINGTON (AFP) - The United States imposed sanctions on Wednesday on supporters of Syrian President Bashar al-Assad's government, including a middleman it alleged buys oil for the regime from the Islamic State in Iraq and Syria (ISIS) group.

"The Syrian government is responsible for widespread brutality and violence against its own people," said Adam Szubin, acting under secretary for terrorism and financial intelligence, in a statement announcing the sanctions action.

"The United States will continue targeting the finances of all those enabling Assad to continue inflicting violence on the Syrian people."

The Treasury Department named four individuals and six entities for sanctions for their support of the Assad regime, "including a middleman for oil purchases by the Syrian regime from the Islamic State of Iraq and the Levant (ISIL)," another acronym for ISIS.

The department highlighted "ongoing government of Syria ties to ISIL."

Sanctions were imposed on George Haswani, a Syrian national, and his company, HESCO Engineering and Construction Company.

"Haswani is a Syrian businessman who serves as a middleman for oil purchases by the Syrian regime from ISIL. HESCO is a Syrian engineering and construction company that operates energy production facilities in Syria, reportedly in areas controlled by ISIL," the Treasury Department said.

Other sanctions targets included Russian Financial Alliance Bank, Primax Business Consultants Limited, and Belize-based Kremsont Commercial.

The sanctions forbid US individuals or entities from doing any business with those on the blacklist, restricting their access to international financial networks crucial to doing business.