Iran's President Mahmoud Ahamadinejad announced on Tuesday that Iran is installing 6,000 new centrifuges at an uranium enrichment plant. The announcement drew sharp criticism from the United States and is expected to deepen the political rift between Iran and the West.  For VOA, Aya Batrawy has more from our Middle East bureau in Cairo.

President Ahmadinejad announced that Tehran is expanding its nuclear enrichment program at the Natanz nuclear plant by installing 6,000 new uranium enrichment centrifuges there.

The Iranian president said the new phase began on Tuesday.   

Last year, Iran announced that it had successfully installed, and was operating, 3,000 centrifuges at Natanz.

Uranium gas is enriched in cascades of centrifuges linked together.  The result can be low-grade fuel used for generating electricity, or higher-grade fuel appropriate for nuclear weapons.

Speaking to a crowd near the nuclear power station in the city of Bushehr, Mahmoud Jafarai, a plant official, confirmed that Iran is moving ahead with nuclear enrichment.

The Bushehr plant is being built by Russia.  But although the uranium for the plant is being enriched in Russia, Jafari told the crowd that Iran has reached an irreversible point in nuclear technology and that Western pressure will only strengthen Iran in defending its national interest.

The crowd responded with cheers chanting, "Nuclear energy is our absolute right."

Following Mr. Ahmadinejad's announcement on Tuesday, the French foreign minister told reporters in Paris that the international community must consider toughened sanctions if Iran does not address concerns about its nuclear program.

In Washington, Secretary of State Condoleezza Rice said she is unable to substantiate Iran's claims.

"I don't think that the underlying situation has changed which is that Iran faces three separate U.N. Security Council resolutions," she said.  "Iran faces continued isolation in the international community."

The United Nations Security Council has already passed three sets of sanctions against Iran for refusing to halt its enrichment program.  

Iran has long defended what it claims is its right to enrich uranium and says its nuclear program is strictly for peaceful energy purposes.

But the United States believes that Iran is working to develop a nuclear weapon.

Iran says it hopes to install some 54,000 centrifuges at Natanz.