WASHINGTON (Reuters) – More U.S. or international sanctions will not persuade Iran to back down on its nuclear program and could lead to “confrontation” with the West, Iranian Foreign Minister Manouchehr Mottaki said in an interview published on Thursday.

Speaking this week to National Public Radio’s “All Things Considered” program, Mottaki dismissed two sets of U.N. sanctions imposed on Iran since December and said tougher penalties would not work.

“In today’s world, the instrument of sanctions is no longer effective,” he said according to a report on the NPR Web site which was to be broadcast by the network later on Thursday.

U.S. officials and experts have insisted for some time that U.S. and U.N. sanctions are having a significant effect on Tehran, especially on its ability to access the international financial system.

A third U.N. sanctions resolution is under discussion by the United States, other permanent members of the U.N. Security Council — China, Britain, France and Russia — and Germany.

Mottaki told NPR the new resolution would not force Iran to halt its uranium enrichment program, which the United States and its allies say is aimed at fueling nuclear weapons but Tehran insists is intended to produce electricity.

“It will be the start of a confrontation,” he said.

Although Mottaki gave no details on what he meant by confrontation, NPR quoted senior Iranian officials as suggesting Iran might stop cooperating with the U.N. International Atomic Energy Agency, which inspects nuclear facilities, or withdraw from the nuclear Non-Proliferation

Treaty.

Military action to delay Iran’s nuclear capability is often discussed in Washington as a possible U.S. option.

But the report described Iranian officials as “supremely confident” that turmoil in Iraq and President George W. Bush’s weakened political standing meant the United States would not

launch an attack.

“Iran’s leadership appears more united than ever about its nuclear program and how to deal with the challenges to it,” the report said.