KAMPALA, Uganda (AP) — A Belgian businessman sanctioned by the U.S. over allegations of illicit gold trade in Congo said Friday the action undermines efforts to improve transparency in a region seeing rising official exports of the mineral.

The U.S. announced sanctions late Thursday targeting Alain Goetz and African Gold Refinery, a Uganda-based company that has been in business since 2014. The company is among several linked to Goetz that are "involved in the illicit movement of gold valued at hundreds of millions of dollars per year" from Congo, the Treasury Department said in a statement.

The illicit movement of gold threatens Congo's peace and stability, it said, charging that more than 90% of Congo's gold is smuggled to neighboring countries such as Uganda and Rwanda where it's "then often refined and exported to international markets, particularly the UAE."

Congo's expansive eastern provinces have long been wracked by sporadic armed conflict, and monitoring groups assert that control of the minerals trade fuels the violence.

The new sanctions include the blocking of U.S.-based assets owned by Goetz and his companies.

But Goetz denied the allegations in a statement emailed to The Associated Press, saying he has no recent business ties with Congo. "I have not been to (Congo) in more than 20 years," he said. "I have not kept any active contacts within (Congo) either."

He warned that sanctions against African Gold Refinery would hurt efforts to improve transparency in the gold business by potentially offering informal traders "a safe haven" again.

"International organizations can now easily verify information and quote figures because of the transparency that I laid a foundation for with the launch of African Gold Refinery," he said. "This transparency is what the U.S. has just placed at great risk with these sanctions."

The African Gold Refinery, worth $15 million and the first of its kind in East Africa, drew attention over the years from activists concerned that minerals from conflict-prone countries in the region were among its raw materials.

The refinery, which was inaugurated by Ugandan President Yoweri Museveni, is located in the lakeside town of Entebbe, about 44 kilometers (27 miles) from the capital, Kampala.

The value of gold exports from Uganda has risen steeply in recent years, though not much is mined locally. Artisanal miners produce small quantities, but gold regularly is Uganda's second most valuable export commodity, after coffee, according to government figures.