An Iranian heavy water plant will dive into circulation on Saturday, and President Mahmoud Ahmadinejad held the open ceremony at 10:OO a.m.(0630 GMT) at the plant in the town of Khondab, near Iran's central city of Arak,some 230 km southwest of Tehran.

The heavy water plant will be used to feed a neighboring nuclear research reactor which is under construction. The research reactor is going to be completed in 2009. It could produce plutonium at the appointed time.

The chief of Iran's Atomic Energy Organization, Gholam Reza Aghazadeh, and his deputy, Mohammad Saeedi, was accompanying the president to the inauguration ceremony.

According to a witness, the reactor and the heavy water plant were highly protected by dozens of anti-aircraft guns. Iran feared that the United States and Israel may launch an air raid onits controversial nuclear facilities.

A top official of the reactor said the inauguration ceremony meaned the heavy water nuclear reactor had entered another phase of production.

The facility now has the ability to produce up to 16 tons of heavy water a year, said Manouchehr Madadi.

Meanwhile, Mohammed Saeedi said on state-run television that the under constructing heavy water reactor is "one of the biggest nuclear projects" in the country.

The state television also quoted Iranian Foreign Ministry spokesman Hamid Reza Asefi as saying that "the Islamic Republic believes the inauguration of this complex within the framework of its legal and international rights".

"Inaugurating the heavy water production plant in Khondab is a big step toward using Iran's right, which means reaching peaceful nuclear technology," he added.

Iran's top officials recently have said that Iran had made fresh achievements in its peaceful nuclear activities and will soon announce them.

The Western countries have been worried that Iran would divert the use of plutonium for developing nuclear weapons. The International Atomic Energy Agency (IAEA) in February asked Iran to think twice on its plan to build a heavy water research reactor in Khondab.

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.

Iran's top nuclear negotiator Ali Larijani has just issued an official reply to the six-nation nuclear package to the international community, but there's no sign that Iran promised to halt its enrichment work in the response letter.

The U.S. has accused Iran of secretly developing nuclear weapons under a civilian front, a charge categorically denied by Tehran which says that its nuclear program is for peaceful purposes.