Members of Congress say the United States and European allies must maintain pressure on Iran to give up any efforts to develop nuclear weapons. U.S. officials and experts testified before the House of Representatives International Relations Committee.
Wednesday's hearing took place as tensions continue to rise between Iran, and the United States and European allies, over Tehran's nuclear program.
Iran told the International Atomic Energy Agency meeting in Vienna the United States would suffer, what it called, "harm and pain" for its role in efforts to take Iran to the United Nations Security Council.
Undersecretary of State for Political Affairs, Nicholas Burns, did not comment directly on the Iranian threat, but said there is universal agreement Iran is attempting to seek nuclear weapons.
"In the hundreds of conversations I had with Russians, Chinese, Indians, Europeans, not a single person, not a single official from any of those governments ever said they doubted Iran is trying to seek a nuclear weapons capability," said Nicholas Burns. "There is no international difference of opinion, there is no debate around the world about the essential fact about what Iran is trying to do."
Now that Iran is due to go before the Security Council, Republican committee chairman Henry Hyde says the United States will need the continuing cooperation of the international community.
"We got Iran to the Security Council not by bullying or sanctioning the IAEA's members but by persistent and skillful diplomacy," said Henry Hyde. "We will move forward the same way."
Tom Lantos, the ranking Democrat on the International Relations Committee, says there can be no doubt about Iran's nuclear intentions.
"The Iranians are hell-bent on acquiring nuclear weapons," said Tom Lantos. "If any leader, any place on this planet still doubts this he is in urgent need of medical attention."
In a speech Tuesday, Vice President Dick Cheney strongly reiterated the U.S. position that Iran cannot be allowed to acquire nuclear weapons, adding the Bush administration continues to keep all options on the table.
Robert Joseph, undersecretary of State for Arms Control, referred to that in answering a lawmaker who asked if the United States is prepared to take military action in Iran as it did in Iraq.
Joseph says Iran is accelerating a large-scale uranium enrichment program, with only one logical objective.
"The only plausible explanation for the expansion and urgency of the Iranian enrichment program is to produce fissile material for nuclear weapons as soon as possible," said Robert Joseph.
White House spokesman Scott McClellan said the Iranian statement in Vienna would only further isolate Iran from the rest of the world.
Undersecretary Burns appealed to lawmakers to soften legislation called the Iran Freedom Support Act that proposes to make permanent and strengthen existing U.S. sanctions on Iran for its weapons development efforts and support of terrorism.
Currently supported by 334 of 435 members of the House of Representatives, the act would also sanction companies or nations investing more than $20 million in Iran's energy sector.
Burns says such actions could weaken what he calls the broadened international coalition trying to resolve the impasse with Iran.
"One thing we don't want to do is divide the international diplomatic coalition that we put together," he said.
The Bush administration and lawmakers are also concerned that sanctions do not, to the extent possible, hurt the Iranian people.
The Iran Freedom Support Act is due to come up at the committee level next week.