The United States warned Turkey in recent days about the export to Russia of chemicals, microchips, and other products that can be used in Moscow's military operation in Ukraine, and it could move to punish Turkish companies or banks contravening sanctions, Reuters reported.

Brian Nelson, the U.S. Treasury Department's top sanctions official, visited Turkish government and private sector officials on Thursday and Friday to urge more cooperation in disrupting the flow of such goods.

In a speech to bankers, Nelson said a marked year-long rise in exports to Russia leaves Turkish entities "particularly vulnerable to reputational and sanctions risks," or lost access to G7 markets.

Turkish entities should "take extra precaution to avoid transactions related to potential dual-use technology transfers that could be used by the Russian military-industrial complex," he said in a copy of the speech issued by the Treasury.

In the meetings in Ankara and Istanbul, Nelson and a delegation highlighted tens of millions of dollars of exports to Russia that raised concerns, according to a senior U.S. official who requested anonymity.

"There is no surprise...that Russia is actively looking to leverage the historic economic ties it has in Turkey," the official said. "The question is what is the Turkish response going to be."