Iran's Supreme Leader Ayatollah Ali Khamenei Saturday urged the country's disputed nuclear case to be returned from the UN Security Council to the International Atomic Energy Agency (IAEA), pledging not to give in to the U.S. pressure, the state television reported.

"There's no reason for Iran's nuclear case to stay in the Security Council," the IAEA should handle it by itself, Ali Khamenei, who has the final say on all Iranian matters, was quoted as telling IAEA chief Mohamed ElBaradei.

"The Americans wrongly believe they could force Iran to back up by pressuring Iran on the nuclear issue, but they cannot submit Iranian people by this," he added.

Earlier in the day, President Mahmoud Ahmadinejad, during a personal meeting with ElBaradei, accused the West of pressuring the IAEA over its probe of Iran's nuclear program.

"Some countries think the agency was set up to enforce their policies, this harassed the natural and just conditions," Ahmadinejad said.

The IAEA chief also met with Iran's chief nuclear negotiator Saeed Jalili, who urged the UN atomic watchdog to be more "impartial" over Tehran's nuclear case.

ElBaradei, who was accompanied by his deputy Olli Heinonen, arrived in Tehran on Friday morning to start his two-day visit in Iran, which was the first in over one and a half years.

ElBaradei's visit came as the international community was discussing a new round of sanctions against Tehran which refused to suspend uranium enrichment work.

After more than four years of investigation, the IAEA still cannot decide whether Tehran's nuclear program was just for peaceful purposes or not.

In his last report released in mid-November, ElBaradei said, "Iran has made substantial progress in revealing the nature and extent of its disputed nuclear program, but needs to be more pro- active in providing information."

The United States has accused Iran of trying to develop nuclear weapons under the cover of a civilian nuclear program. Iran denied the accusation and insists its nuclear program is for peaceful purposes only.

The UN Security Council has adopted two resolutions -- one in December 2006 and the other in March of 2007 -- to force Iran to suspend uranium enrichment activities and to give up its nuclear programs.

(Xinhua News Agency January 13, 2008)