The announcement comes as the Obama administration is set to announce new sanctions against Iran later Monday.
Media reports say the U.S. will impose sanctions on goods and services used by Iran's petrochemical industry to discourage foreign companies from investing in it. Iranian petrochemical companies have become increasingly involved in refining gasoline as other Iranian energy firms face international sanctions.
U.S. officials say the Treasury Department also will designate Iran as a territory of "primary money laundering concern." They say the designation will serve as a warning to foreign governments and businesses to scale back their relations with Iranian financial institutions. U.S. companies and individuals already are barred from doing business with Iran.
U.S. officials also say the State and Treasury Departments will expand the number of Iranian companies and organizations facing sanctions for suspected involvement in the Iranian nuclear program.