Iran's supreme leader Ayatollah Ali Khamenei said on Saturday the United States would not be able to bring Iran "to its knees" in a row over sensitive nuclear work the U.S. suspects is aimed at making bombs.
Khamenei also told the visiting head of the U.N. nuclear agency that Iran's nuclear file should be handled by the International Atomic Energy Agency and not the U.N. Security Council, which has imposed two rounds of sanctions on Tehran.
"There is no justification for Iran's case to remain at the U.N. Security Council," official media quoted Iran's most powerful figure as telling IAEA head Mohamed ElBaradei.
ElBaradei met Khamenei and other Iranian leaders during a two-day visit to Tehran to push for more cooperation in resolving questions about Iran's atomic activity, which the United States fears will be used to make warheads.
U.S.-Iranian tensions increase
His visit coincides with renewed Iranian-U.S. tension over a naval incident in Gulf last Sunday. Washington says its ships were threatened by Iran, Tehran calls it a routine contact.
President Bush is also visiting the Middle East this week to seek Arab support in reining in Iran and has repeated his assertion that Iran was a "threat to world peace".
Washington is pushing for a third set of sanctions on Iran for refusing to halt uranium enrichment work, as demanded by the United Nations. Iran says it wants to master enrichment technology so that it can make fuel to generate electricity.
Khamenei was defiant in his meeting with ElBaradei, who is seeking to defuse a standoff that has helped send oil prices to record levels and sparked fears of a military confrontation.
"America's problem with Iran is beyond the nuclear issue," state television quoted Khamenei as saying.
"Americans are mistaken by thinking that by pressuring Iran over the nuclear issue they can break Iran. By bringing this and other issues to the fore, they cannot bring the Iranian nation to its knees," he said.
'Accelerated cooperation' from Iran
The IAEA has sought to verify that Iran's uranium enrichment program is geared solely to producing civilian energy.
Khamenei said that "building or using nuclear weapons is against" Islamic sharia law.
The IAEA chief, who told reporters on Friday he was looking to "accelerated cooperation" from Iran, also held talks with President Mahmoud Ahmadinejad during his visit but it was not immediately clear whether his visit yielded concrete results.
A diplomat close to the IAEA said before ElBaradei's visit that an agency inquiry stonewalled by Iran for years until August had entered a final phase with Iran addressing U.S. intelligence about past attempts to "weaponize" atomic material.
Iran said in August it would answer outstanding questions about its nuclear past but an end-of-year target for completing the process passed with the sensitive issues still unresolved.