The United States has imposed wide-ranging new sanctions against Iran in a further effort to pressure Tehran to halt nuclear activities seen as weapons-related. Targets of the new sanctions include the Iranian defense ministry and the Revolutionary Guards Corps. VOA's David Gollust reports from the State Department.

The measures announced by Secretary of State Condoleezza Rice and Treasury Secretary Henry Paulson are the most severe against Iran to date, and mark the first time that the United States has targeted another country's military for sanctions.

The sanctions package, which had been under consideration for months, includes measures aimed at isolating three of Iran's biggest state-owned banks - Banks Melli, Mellat and Saderat - for involvement in weapons proliferation or financing terrorism.

Iran's defense ministry and the Revolutionary Guards Corps are also being sanctioned for proliferation activity, while the elite branch of the guards corps - the Quds Force - is being penalized for providing material support to terrorist groups including Hezbollah in Lebanon and the Taliban in Afghanistan.

At a joint press event with her Treasury counterpart, Secretary Rice said the sanctions were prompted by Iran's refusal to heed international demands that it drop what she termed its "unwise campaign" for a nuclear weapons capability.

Rice said an offer to Iran for civil nuclear power assistance and diplomatic benefits remains on the table if it gives up its pursuit of a nuclear fuel cycle.

"If the Iranian government fulfills its international obligation to suspend its uranium enrichment and reprocessing activities, I will join my British, French, Russian, Chinese and German colleagues and I will meet with my Iranian counterpart anytime, anywhere," she said.

"We will be open to the discussion of any issue. But if Iran's rulers choose to continue down a path of confrontation, the United States will act with the international community to resist these threats of the Iranian regime," she added.

The sanctions forbid U.S. citizens or companies from doing business with any of the targeted Iranian institutions and freeze any assets they may have in banks under U.S. jurisdiction.

Senior administration officials acknowledge that Iranian entities like the Revolutionary Guards are unlikely to have any assets directly vulnerable to the sanctions.

But Treasury Undersecretary for Terrorism Stuart Levey told reporters the blacklisting of major Iranian banks by United States for terrorism and proliferation links will be a powerful incentive for other banks and governments to cease doing business with them.

"When we take action in this kind of way and identity individual entities or even individual people who are engaged in specific illicit conduct, financial institutions around the world do listen," said Levey. "They do not want to do business with these people. They do not want to do business with people who are proliferators. They do not want to do business with people who are terrorists."

The sanctions announcement came against a background of toughening rhetoric from the Bush administration about Iran, including a warning by Vice President Dick Cheney earlier this week of serious consequences if it continues its present course.

Undersecretary of State for Political Affairs Nicholas Burns said the parties are still in the middle of a diplomatic process and that the United States does not see conflict with Iran as either inevitable or desirable.

"This decision today supports the diplomacy, and in no way, shape or form does it anticipate the use of force," he said. "The president has never taken that option off the table, and quite rightly so. But we are clearly on a diplomatic track and this initiative reinforces that track."

Burns said he hopes the U.S. move will give new impetus to efforts in the U.N. Security Council for a third sanctions resolution against Iran, which he said is six months overdue.