The US decision to cut business between Bank Saderat and the US financial system is "a mistake," Foreign Ministry spokesman Hamid-Reza Asefi was quoted by IRNA as saying.

"We believe that imposing restrictions on Bank Saderat is just another childish behavior by the United States, which would produce no result for them," Asefi said.

"Washington has proved that it would use all means to advance its wrong policies," he added.

A press release issued on Sunday by the bank's public relations department said all of its banking affairs, both at its domestic and overseas branches, are conducted according to Islamic system and international regulations.

Washington's "hostile attitude will not be effective" because the bank has an extensive banking and information network, an international communication system and extensive banking exchanges with foreign banks, especially in Europe, the press release said.

The U.S. government imposed sanctions on the Iranian bank on Friday, barring it from dealing with U.S. financial institutions, even indirectly.

The move against Bank Saderat was announced by Stuart Levey, the Treasury's undersecretary for terrorism and financial intelligence, who accused the major state-owned bank in Iran of funding "terrorist groups," including Hezbollah.

Levey said since 2001 a Hezbollah-controlled organization had received 50 million U.S. dollars directly through Bank Saderat. He said the U.S. government would also persuade European banks and financial institutions not to deal with Bank Saderat.