US Secretary of State Condoleezza Rice called her major power counterparts on Tuesday in a bid to spur tough negotiations at the United Nations over a sanctions resolution against Iran, a senior US official said.
Rice urged the foreign ministers from the other permanent UN Security Council members -- Britain, China, France and Russia to overcome the differences that have prevented agreement on the sanctions package, Under-secretary of State Nicholas Burns said.
"She put forward the proposal that we should try to work extremely hard to get that resolution passed as quickly as possible," Burns said.
"We are working very hard at the UN Security Council to push for a resolution," he said.
Iran faces the sanctions after rejecting an earlier UN resolution demanding it freeze a uranium enrichment program many fear is a cover for developing nuclear weapons.
Earlier another senior US official said North Korea's sudden decision on Tuesday to give up its nuclear arsenal in the face of UN sanctions had provided a model for confronting Iran's uranium program.
"The Iranians certainly are watching whether or not the world was going to react to what North Korea did," said State Department spokesman Sean McCormack, referring to Pyongyang's first test of a nuclear weapon on October 9.
"The (UN) Security Council clearly did act, so I think in that sense it was a lesson for Iran in terms of the will of the international community to act," he said.
Diplomats at UN headquarters in New York meanwhile said another meeting of five veto-wielding Security Council members plus Germany to discuss the Iran sanctions resolution was unlikely to take place before on Friday at the earliest.
The six are working on a draft resolution drawn up by Britain, France and Germany urging nuclear and missile-related sanctions against Tehran.
Washington has so far refrained from co-sponsoring the draft in a sign it is seeking tougher measures than those proposed by its European partners.
US officials have notably said they want clear guarantees that a nuclear power station being built in Iran by Russia will not give Tehran access to technology or materials that could be used in a weapons program.
Russia and China, both major trading partners of Iran, are for their part believed to be trying to soften the resolution.