The U.S. designation named the Revolutionary Guard Corps as a proliferator of weapons of mass destruction, and labeled its Quds Force unit as a supporter of terrorism. It said Iran's Bank Melli and Bank Mellat had helped finance Tehran's proliferation program, and that Bank Saderat has taken part in financing terrorism.
Five Revolutionary Guard Corps leaders, nine other businesses and the Iranian Ministry of Defense and Armed Forces Logistics also face sanctions.
Iran denies U.S. accusations that its uranium enrichment program is aimed at developing nuclear weapons, saying it is only for civilian energy purposes. Tension between Washington and Tehran has been heightened during the last year by U.S. charges that Iran is supplying Iraqi insurgents.
Reports in August that U.S. officials were considering even more drastic sanctions touched off an outcry among Europeans, who read such a move as a clash with Iran over Iraq rather than over nuclear enrichment. Europeans told U.S. officials that they did not want to conflate the two issues.
U.S. officials have been frustrated recently by the Europeans' reluctance to impose sanctions through the European Union.
At a meeting last week in Brussels, Britain and France showed support for the idea, whereas Italy and Austria opposed it and German officials were lukewarm.
U.S. Undersecretary of State R. Nicholas Burns, the administration's point person on Iran, said in an interview that the sanctions would not alienate European allies.
"Countries want to see diplomacy succeed, and you'll see the Europeans go ahead with their own [sanctions] effort," he said. He said the United States had heard from many who support the move, although he acknowledged that "the reaction has not all been positive."
J. Scott Carpenter, a top State Department official on the Middle East until last month, favors the new package but said European cooperation was vital.
At this point "only they can add anything to the sanctions regime," said Carpenter, now a scholar at the Washington Institute for Near East Policy. He said he believed the U.S. package would make it more difficult to win over the divided European community.
Suzanne Maloney, a top Iran analyst at the State Department until this year, said the sanctions appeared to be a recognition by the administration that European cooperation was unlikely.
