Iran said Wednesday it plans to shift its production of enriched uranium to an underground bunker and triple its production capacity in what observers are terming a defiant response to accusations it is trying to produce nuclear weapons.

"This year, under the supervision of the [International Atomic Energy] Agency, we will transfer 20 per cent enrichment from the Natanz site to the Fordow site and we will increase the production capacity by three times," Fereydoun Abbasi-Davani, the head of Iran's atomic energy agency, told reporters , told state broadcaster IRIB.

Iran only disclosed the existence of the Fordow site, in a mountain bunker, in September 2009, after Western intelligence had detected it and said it was evidence of covert nuclear work.

The Fordow enrichment site near Qom.

Condemnation

The decision to move production to the Fordow site and increase output drew immediate condemnation from Western nations, which have imposed a series of sanctions on Iran to try to force it to halt enrichment — a process that can make weapons-grade material if carried out properly.

"This announcement is a provocation," the French Foreign Ministry said in a statement.

"It reinforces the international community's existing concerns over the intransigence of the Iranian authorities and their persistent violation of international law."

U.S. IAEA envoy Glyn Davies said the plan was Iran's "most recent brazen example of its deepening non-compliance" with IAEA regulations.

Rising Tensions

The move comes shortly after Iranian lawmakers toured the Israel-Lebanon border and Iran's announcement earlier this week it had dispatched submarines to the Red Sea.

The Fars news agency, which is close to Iranian military officials, said the submarines will collect data in international waters and identify warships of other countries.

The report quoted an unnamed government official as saying the submarines accompanied Iranian warships on an anti-piracy route in the Gulf of Aden before they moved into the Red Sea earlier this month.

Israel previously deployed a flotilla of its own submarines to the the Persian Gulf.