President Barack Obama and Secretary of State Hillary Rodham Clinton, arguing that an orchestrated series of global sanctions has brought more economic pain than Iran's government anticipated, are making a renewed appeal to Iranian leaders to reopen negotiations on the country's nuclear programme.

The administration's opening to Iran comes as evidence mounts that gasoline shipments to the country have slowed; that at least some banks, from Europe to Pakistan, have cut off dealings with the country for fear that they will lose access to the U.S. financial system; and that Iranian officials have been unable to get foreign investment for several multibillion-dollar oil and gas projects.

Much of that evidence has been reported by the local news media in the Persian Gulf region and is difficult to confirm, but officials with the U.S. Treasury Department say they also believe Iran is having trouble attracting investment for oil and gas projects.

Ms Clinton argued that “the scope and reach” of sanctions adopted over the past two months in the U.S., Europe and parts of Asia “have had real bite,” and have given the West new leverage.

Still, both Ms Clinton, in a 20-minute telephone conversation on Friday, and Mr. Obama, in an unusual assessment to editorial writers and columnists at the White House last week, acknowledged that Iranian leaders might be unwilling to give up the nuclear programme — a huge source of national pride — despite the escalating cost.

“It may be that their ideological commitment to nuclear weapons is such that they're not making a simple cost-benefit analysis on this issue,” Mr. Obama told the journalists.

In a sense, the administration's latest overtures are testing the theory behind its decision to push for ever tightening sanctions: that the financial punishment would bring Iran to the negotiating table.

Critics have questioned the approach from the beginning, and even one of Mr. Obama's advisers said while Iran had indicated a willingness to start some kind of talks in September, there was always the chance that the sanctions would backfire, leading the country to “speed up the nuclear programme.”

There is also the chance that Iran, which says its nuclear programme is for peaceful uses, will figure out ways around the international crackdown, as it has done with past sets of sanctions.

Mr. Obama's and Ms Clinton's back-to-back public statements appeared to be part of an effort to signal to the Iranian people that the country would continue to suffer if the government did not find what Ms Clinton called “a pathway” to negotiations. A senior White House official, who spoke on the condition of anonymity, said that in coming days, the administration would stress its view that “the economic difficulties experienced by the public” in Iran are being caused by choices the Iranian government is making. — New York Times News Service

More In: Comment | Opinion