The Biden Administration and the European Union are putting pressure on Turkey to enforce Russia sanctions amid concerns that its banking sector is a potential backdoor for illicit finance, the Financial Times reported on Thursday.

What Happened: The U.S. authorities are focusing on Turkish banks that have integrated into Mir, a Russian card payment system for electronic fund transfers, two western officials aware of the discussion told the publication. The EU, too, is preparing a delegation to express its concerns directly to Turkish officials.

See Also: Narendra Modi To Have Dinner With Vladimir Putin, Xi Jinping In Uzbekistan Today: What's On Agenda?

Why It's Important: The development comes as the Western countries pivot towards tighter implementation of existing sanctions on Russia for its war in Ukraine rather than imposing new measures.

“You’re going to see us kind of focus on financial sector evasion,” the first Western official told the publication. “We’ll send a message very clearly that, for example, third-country financial institutions should not be interconnecting with the Mir payment network because, you know, that carries some sanctions-evasion risks.”

Another source involved in this month’s talks between the E.U. and U.S. on sanctions enforcement said, “We need to close loopholes,” citing Turkey as the major target.

President Recep Tayyip Erdoğan’s country, which is also Vladimir Putin’s ally and a NATO member, has pursued what it calls a “balanced” approach toward the Ukraine war. Erdoğan, who is due to meet Putin on Friday, said last month that there is “serious progress” on expanding Mir in Turkey.

See also: Vladimir Putin And Xi Jinping To Discuss Ukraine And Taiwan Issues: China 'Clearly Understands The Reasons That Forced Russia' To Invade Kyiv