WASHINGTON: The US on Tuesday imposed sanctions on Samer Foz, a Syrian industrialist behind high-end developments, including the Four Seasons hotel in Damascus, for allegedly enriching President Bashar Assad.

"This Syrian oligarch is directly supporting the murderous Assad regime and building luxury developments on land stolen from those fleeing his brutality," Sigal Mandelker, the undersecretary of the treasury for terrorism and financial intelligence, said in an announcement.

Sanctions were placed on Syrian businessman Foz and his family, who have close ties to Assad and who Washington said has made millions by developing properties on land seized from those who have fled the Syrian war.

The sanctions were being placed on Foz, his siblings Amer and Husen, and the family-owned Aman Holding, a company run by the Foz family from the coastal city of Latakia, the Treasury said.

Foz-owned ASM International General Trading and its affiliates throughout the Middle East were also included in the sanctions. ASM is involved in grain and sugar trade, and oil field operations.

"Samer Foz, his relatives, and his business empire have leveraged the atrocities of the Syrian conflict into a profit-generating enterprise," Sigal Mandelker, undersecretary for terrorism and financial intelligence, said in a statement.

The Treasury Department said Foz had shipped into Syria oil from its ally Iran, despite unilateral US sanctions on all exports out of the Islamic republic.

In the notice, the Treasury Department also said that Foz had taken advantage of an order issued by Assad in 2012 to expel residents of poorer areas to make way for luxury construction.

"This tactic -- taking over property owned by Syrian citizens and handing the land to wealthy regime insiders to develop in exchange for revenue sharing -- has emerged as Assad's go-to strategy for high-end reconstruction in war-torn Syria," the Treasury Department said.

Under the sanctions, any of Foz's US assets will be frozen and any US transactions with him or his properties forbidden.

The US Treasury said it was also sanctioning Synergy SAL and BS Company, which have imported tens of thousands of metric tons of Iranian oil into Syria.

Meanwhile, the Four Seasons hotel has become a base for UN employees working in Syria, a point of controversy for Assad opponents who question where the money paid by international staff goes.