The BBC reports that Turkey is being warned for possible misuse of gold imported from Venezuela, which is in political crisis as the opposition leader claims the right to presidency and many countries siding with him, have called for the resignation of current president Nicholas Maduro.

BBC quotes a “senior Western diplomatic source” as saying that there is growing concern that at least part of the gold exported to Turkey ends up in Iran, violating U.S. sanctions.

Iran and Venezuela’s Maduro are close allies and Iranian officials have voiced strong support for his government.

Iran’s President Hassan Rouhani on Saturday called the U.S. a hegemonic power for supporting Maduro’s rival and freezing Venezuela’s assets in favor of the opposition.

Turkish president Recep Tayyep Erdogan has also publicly voiced support for Maduro, which was seen stemming from his desire to support another authoritarian leader.

The BBC says that Venezuela’s gold exports to Turkey are soaring, reaching close to one billion dollars last year. Sources have also told BBC that Ankara has received warnings. The United Arab Emirates and Russia are also destinations for Venezuela’s gold, but Turkey is now seen as the biggest problem.

Opponents accuse the Venezuelan government of mining gold in illegal ways, using mafia networks to control small miners with use of violence.