The United Nations Security Council is scheduled to vote later Saturday on a resolution that will impose new sanctions on Iran for its refusal to stop enriching uranium.
Major powers expect that the measure will be unanimously approved.
Iran's Foreign Minister Manouchehr Mottaki will attend the Council meeting. He is set to defend what Iran says is its right to pursue a peaceful nuclear power program.
A U.S. State Department spokesman, Sean McCormack, says he expects Tehran to try to divert attention from the fact that Iran is ignoring the international community by continuing with its enrichment program.
The new resolution builds on penalties already in place since December. It calls on Iran to halt uranium enrichment, bans all Iranian arms exports, and also freezes the assets of 28 more Iranian individuals and institutions believed to have ties to nuclear weapons.
U.S. officials say the resolution includes core elements agreed upon by the five permanent Security Council members - Britain, China, France, Russia and the U.S. - plus Germany.
The United States and its allies accuse Iran of trying to develop nuclear weapons. Tehran denies the charge.
Iranian President President Mahmoud Ahmadinejad was to have come to New York, but he called off his trip.
Iran accuses the United States of issuing visas too late. But a State Department spokesman says all visas were approved and handed over to Iranian representatives in Switzerland Friday.
The U.S. spokesman says Mr. Ahmadinejad is not willing to stand before the Security Council and face criticism for defying the international community.
Some information for this report provided by Reuters, AFP and AP.