The Treasury Department, which announced the sanctions, also named 21 companies that it said are, in effect, fronts for the Iranian government in its pursuit of illicit weaponry, including nuclear arms.
By publicly naming the companies, the United States said it was making it easier for US companies to comply with their legal obligation not to do business with the Iranian government.
Taken together, the actions reflect an Obama administration strategy of ratcheting up economic and political pressure on Iran to limit its support for Islamic extremism in the Middle East. A parallel goal is to coax Iran into international negotiations over its nuclear program.
Robert Einhorn, the State Department official who oversees the enforcement of sanctions against Iran and North Korea, told reporters in Seoul on Tuesday that the United States has no choice but to pressure Iran because earlier offers to negotiate were rejected.
"Pressure is not an end in itself," Einhorn said.
"Instead, sanctions are intended to bring Iran's leaders to the conclusion that their country would be better served by ending its noncompliance with its international obligations and starting to address serious concerns about Iran's nuclear intentions." Iran insists its nuclear program is designed to generate electricity, not build weapons.
Stuart Levey, the Treasury Department's undersecretary for terrorism and financial intelligence, said sanctions against some Iranian organizations and senior officials are meant to complicate the groups' efforts to support extremist movements in the Middle East.
Asked about the Treasury actions, State Department spokesman P.J. Crowley said the moves are in line with a strategy that is beginning to have some effect on Iran's strategic thinking.
"It is getting increasingly difficult to do business in Iran," Crowley said. "The cost of doing business for Iran is going up. And we are encouraged by what we're seeing." The new sanctions expand the list of individuals and groups with whom Americans are not permitted to do business. The sanctions also freeze any assets of the organizations and officials that currently are under US jurisdiction.
Treasury targeted two officers in the Qods force, an elite arm of the Islamic Revolutionary Guard Corps, for providing money and weapons to militant groups the United States has designated terrorist organizations: Hezbollah, Hamas and Palestinian Islamic Jihad. It also targeted two other officers alleged to have provided money and "material support" to the Taleban in Afghanistan.
The administration asserts that the Qods force provides select members of the Taleban with weapons, money, logistical support and training.
Treasury also imposed sanctions on the director of the Iranian Committee for the Reconstruction of Lebanon, for what it called financial, material and logistical support to Hezbollah.
It also sanctioned the Lebanon branch of the Imam Khomeini Relief Committee, and its director, for being owned or controlled by Hezbollah and for providing Hezbollah with money and other support.
Treasury also imposed sanctions on Razi Musavi, an Iranian official based in Syria, for supporting Hezbollah.
