The United States is imposing sanctions against three individuals in Guyana, including a public official, on accusations of corruption, according to the State Department.

A Tuesday statement names Guyanese official Mae Thomas, businessman Nazar Mohamed and his son Azruddin Mohamed, as well as their company, Mohamed’s Enterprise. Guyanese news media reports say all three have previously denied wrongdoing.

The State Department says Mohamed’s Enterprise defrauded the government of Guyana by failing to declare gold imports and exports and avoiding payment of more than $50 million in duty taxes.

It said Thomas, the former permanent secretary to Guyana’s minister of home affairs, and the current permanent secretary to the Ministry of Labor, misused her position to assist Mohamed’s Enterprise and Azruddin Mohamed in exchange for cash and high-value gifts.

Gold is one of Guyana’s main exports and the country’s gold is sold and traded on international markets, including the U.S., Canada, United Arab Emirates and the European Union.

“Today’s action underscores our commitment to holding accountable those who seek to exploit Guyana’s underdeveloped gold sector for personal gain,” said Brian Nelson, U.S. under secretary of the Treasury for terrorism and financial intelligence.

The sanctions prohibit Americans from conducting transactions with the designated individuals and companies and freeze any of their property or assets that are under U.S. jurisdiction.