Annan will discuss "different issues" with Iranian officials during his visit on that day, two days after a UN Security Council deadline related to the country's disputed nuclear issue, Hamid Reza Asefi said.

The Security Council has recently adopted a resolution urging Tehran to suspend by Aug. 31 all enrichment-related and reprocessing activities, including research and development, or face the prospect of sanctions.

On June 6, EU foreign policy chief Javier Solana also presented Iran with a package agreed on by the five permanent members of the UN Security Council, namely the United States, Russia, China, France and Britain, plus Germany concerning the Iranian nuclear issue.

On Tuesday, Iran's top nuclear negotiator Ali Larijani delivered Tehran's written response to the package and urged the six nations to get back to negotiations, saying Iran was ready to start "serious talks" over its nuclear program.

Meanwhile, an Iranian heavy water plant dived into circulation on Saturday in the town of Khondab, near Iran's central city of Arak, some 230 km southwest of Tehran.

The West has accused Iran of trying to produce nuclear weapons under a civilian cover, a charge denied by Tehran.

Iran, however, says it needs to enrich uranium as a peaceful, alternative energy source and has the right to do so under the nuclear Non-Proliferation Treaty.