US administration officials told impatient lawmakers Tuesday that they are ready to take swift and substantial action against Iran if it disregards current diplomatic efforts to stop its alleged nuclear weapons program. At a Senate Banking Committee hearing, lawmakers expressed skepticism that Iran would negotiate in good faith. They said they would not wait long before acting on legislation to impose tough new sanctions on the Teheran government. Banking Committee Chairman Sen. Christopher Dodd, a Democrat, said he planned to move forward this month on a proposal to extend restrictions on financial transactions, impose new sanctions on oil and gas pipelines and tankers, restrict exports of certain refined petroleum products to Iran and impose a broad ban on imports from Iran. He said the world, and particularly the Iranian government, must know that the United States won't wait long to act and Congress wants action: "The fear here collectively is that the Iranian government is taking us to the cleaners on this issue." Administration officials at the hearing stressed that sanctions against Iran are most effective if imposed by a united international coalition. Undersecretary of the Treasury Stuart Levey told the panel: "The less united we are in applying pressure, the greater the risk our measures will not have the impact we seek." Last week, the United States and five allies held talks with Iran in Geneva where Iranian officials agreed to open its newly disclosed nuclear plant to UN inspectors and take other steps to show it is not trying to develop nuclear weapons. President Barack Obama said the talks were a "constructive beginning," while adding that his administration was working with Congress on new actions targeting Iran's energy, financial and telecommunications sectors in the event Iran did not live up to its promises. James Steinberg, deputy secretary of state, told the hearing that the administration was "realistic" about prospects for engaging with the Iranian government. But he said the current dual-track strategy of diplomatic talks with the threat of punitive action was helping develop a strong consensus within the international community if the talks falter. He said it would be clear by the end of this month whether Iran is serious about meeting two specific commitments: providing access to the newly revealed nuclear facility and shipping low enriched uranium out of the country. "Our patience is not unlimited," he added. Levey said that with targeted sanctions backed by a broad coalition of governments, "we can at the very least demonstrate to the Iranian government that there are serious costs to any continued refusal to cooperate with the international community." International concerns about Iran's nuclear work grew Tuesday with an Iranian newspaper report that the country plans to install a more advanced type of centrifuge at its newly revealed uranium enrichment site near the holy city of Qom. Iran insists its enrichment work is only meant for use in generating power, but Washington and its allies are suspicions of Teheran's intentions and fear its mastery of the technology will give them a pathway to weapons development. Despite years of diplomatic efforts, Iran has "continued to choose a collision course with the free world," said Sen. Sam Brownback, a Republican, Brownbeck and Sen. Bob Casey, a Democrat, are promoting a bill that would allow state and local governments and universities to divest their assets from any company that invests $20 million or more in Iran's energy sector.