US Secretary of State Condoleezza Rice, urging UN members to enforce sanctions imposed on North Korea for its nuclear weapons test, warned on Monday that Iran was closely watching the outcome.
Rice spoke on the eve of a four-nation swing to discuss the nuclear sanctions, including stops in China and Russia which have been resisting US calls for tougher action against North Korea and Iran.
"The Iranian government is watching and it can now see that the international community will respond to threats from nuclear proliferation," she told reporters.
Rice warned Iran that it could face sanctions and international isolation over its nuclear program such as those faced by North Korea.
"I expect the Security Council to begin work this week on an Iran sanctions resolution," she said. "So the Iranian government should consider the course that it is on, which could lead to simply to further isolation."
The Council unanimously voted for wide-ranging sanctions against North Korea over its defiant nuclear test last week.
The United States is gathering international support to also punish Iran for defying a Council decision calling on the Islamic republic to halt uranium enrichment, a process that could lead to nuclear bomb-making.
After four rounds of unsuccessful talks aimed at securing an enrichment suspension, the European Union is set to return the Iranian nuclear file to the
UN Security Council on Tuesday for possible enforcement action.
"The greatest challenge to the non-proliferation regime comes from countries that violate their pledges to respect the Non-Proliferation Treaty. The North Korean regime is one such case, but also so is Iran," Rice said.
But Iran, a member of the Nuclear Non-Proliferation Treaty, said it would not buckle under pressure.
"Pressure and threats against Iran's nuclear program will not affect Iran in any way," the student news agency ISNA quoted Iranian President Mahmoud Ahmadinejad as saying.
Uranium enrichment lies at the heart of Western concerns over Iran's nuclear program. The process can be used to make the fuel for civil reactors but in highly extended form can also produce the fissile core of an atom bomb.
Iran insists its nuclear program is solely for civilian energy purposes, but Tehran's arch-foe Israel and the United States suspect the real aim is a covert weapons program.