In another salvo in the US campaign to press the Islamic regime in Tehran over its alleged nuclear plans, Under Secretary of State John Bolton said there was a crisis of noncompliance with the nuclear non-proliferation treaty (NPT).
"If we permit Iran's deception to go on much longer, it will be too late," Bolton said at a meeting to prepare for a conference next year to review the NPT. "Iran will have nuclear weapons."
Iran, dubbed part of US President George W. Bush's "axis of evil" along with North Korea and the former Baghdad regime, has repeatedly denied trying to develop such weapons and claims its nuclear programme is for peaceful civilian purposes.
But the United States has been sceptical about Tehran's pledges to improve cooperation and transparency with the UN's International Atomic Energy Agency (IAEA), saying Iran has reneged on similar vows.
Last week, Bush said any development of an atomic weapon by Tehran would be "intolerable."
The IAEA reprimanded Iran last year for failing to make a full accounting of its nuclear activities, but bowed to international pressure and signed the NPT's additional protocol allowing tougher probes by the watchdog agency.
"Iran's oil-rich environment, grudging cooperation with the IAEA, its deception, and its 18 year record of clandestine activity leads us to the inevitable conclusion that Iran is lying," Bolton said.
Bolton said that while the United States had not pressed the IAEA to report Tehran to the Security Council yet, he expected that the agency would "at some point" need to do so.
"If Iran continues its unwillingness to comply with the NPT, the council can then take up this issue as a threat to international peace and security," Bolton said.
"If the council is unable to do so, it will not only be a blow to our efforts to hold Iran accountable, but also a blow to the effectiveness of the council itself and to the credibility of the entire NPT regime."
Bolton also went after North Korea, which is in an 18-month standoff with the United States over its nuclear weapons programme.
"North Korea's use of the NPT as a cover to hide its nuclear weapons ambitions, and its subsequent withdrawal from the treaty, constitute the clearest example of a state cynically manipulating the NPT to threaten the international community with its nuclear weapons programme," he said.
In October 2002, Washington said the Stalinist state had broken a 1994 nuclear freeze by launching a secret nuclear weapons programme.
Two rounds of six-way talks hosted by China have failed to narrow key differences on how to end the stand-off.
New talks -- which bring together the two Koreas, the United States, China, Russia and Japan -- are to open in Beijing by the end of June.
The United States and Britain are pushing a new Security Council resolution aimed at keeping nuclear, chemical and biological weapons out of the hands of terrorists. A vote is expected on the measure this week.