The US ambassador to the United Nations on Monday called Iran's plans to build an additional 10 uranium enrichment plants "unacceptable," warning they could bring increased international pressure on Teheran. Susan Rice comments came in reaction to comments from Iran's nuclear chief that UN criticism pushed his country to retaliate by announcing the more-ambitious uranium enrichment plans. "We view the Iranian announcement, if it is in fact accurate and implemented, that they intend to build 10 additional facilities as completely inappropriate and further isolating Iran from the international community," Rice told reporters at UN headquarters. One of Iran's vice presidents, Aki Akbar Salehi, told state radio that Iran intended the move as a response to International Atomic Energy Agency demands Friday that the country halt construction of its newly-revealed uranium enrichment facility. On Sunday, Iranian President Mahmoud Ahmadinejad and his cabinet approved plans to build 10 industrial scale uranium enrichment facilities to produce nuclear fuel. The US and its allies fear the facilities could also produce material for a nuclear weapon and have called for an immediate halt to Iran's enrichment program. Iran and the top powers at the UN are deadlocked over a UN-drafted proposal for Iran to send much of its enriched uranium abroad. The United States and other Western powers say the proposal would at least temporary leave Teheran unable to develop a nuclear bomb. US envoy Rice indicated the Obama administration, which favors sanctions and incentives, could soon begin seeking added international sanctions against Iran because of its rejection of UN Security Council demands that it freeze all enrichment. "As Iran makes choices that seem to indicate that it is not at this stage ready and willing to take up the offers on the engagement track, then we will put greater emphasis on the pressure track," Rice said. "Time is short and we are serious about implementing to the fullest extent that dual track policy." Rice said President Obama's offer still stands until the end of the year for Teheran to consider incentives for suspending enrichment offered by the five permanent members of the Security Council - the US, China, Britain, France and Russia - plus Germany. French Foreign Minister Bernard Kouchner said Monday in Paris on France's RTL radio that Iran "is playing an extremely dangerous game."