Turkey’s Banking Regulation and Supervision Agency has revoked the operating license of the Istanbul branch of Iran’s Bank Mellat, according to a decision published in the country’s Official Gazette, as international and U.S. pressure on Tehran-linked financial institutions continues to intensify.

The decision cited a provision of Turkey’s banking law that permits the withdrawal of a banking license when an institution’s continued operations are considered a potential threat to depositors’ rights or the stability of the financial system.

Turkish authorities did not provide further details on the immediate reasons behind the move. The published notice also made no explicit reference to U.S. sanctions against Iran or to any specific operational violations involving the bank.

The decision comes amid Washington’s expanding measures against financial networks it says are connected to Iran, as part of efforts to restrict Tehran’s access to the global financial system.

Earlier this month, the U.S. Treasury Department imposed sanctions on a Turkish investment bank and two affiliated companies, citing alleged links to Iranian financial networks.

The department also said that Turkey and Oman had suspended flights by Iranian airline Mahan Air to their territories following discussions over compliance with U.S. measures targeting Iran.

Bank Mellat, which is headquartered in Tehran, is one of Iran’s financial institutions with operations abroad. The closure of its Istanbul branch raises questions about the future of Iranian banking activities in Turkey.

Although the decision coincides with growing pressure on Tehran, the official notice does not establish that the move was made at Washington’s request or as a direct response to international sanctions. The legal provision cited in the decision therefore remains the stated basis for the revocation.