Nulands remarks were in response to Iran's announcement on Wednesday that it activated a new generation of centrifuges at its Natanz nuclear site in order to accelerate its uranium enrichment activities.
"Today we witnessed the activation of the first cascade of these centrifuges," the head of the Atomic Energy Organization, Fereydoon Abbasi Davani, said in a speech broadcast on state television.
"They increase Iran's capacity to enrich uranium by three times," he said. "This is a strong and documented response to all the sabotage conducted by the West."
The Fars news agency reported that the new centrifuges, said to be made of carbon fiber and domestically produced, were installed in Natanz. Iranian state television carried footage of President Mahmoud Ahmadinejad personally starting one of the centrifuges.
The Natanz facility is largely above ground.
The report comes just hours after Iran announced it would be expanding centrifuge operations at the underground Fordo nuclear facility near Qoms.
Fordo is Iran’s second major uranium enrichment plant, with an older one in the central desert city of Natanz, first revealed in 2002.
The Fordo plant takes uranium fuel enriched to 4 percent purity at Natanz and further enriches it to 20 percent purity, a level that can make fuel for a research reactor in Tehran.
But it is far easier to make bomb-grade fuel from the 20 percent purity concentration than from 4 percent, which has been one source of Western concern about Iran’s ultimate intentions.
The revelation that there are new centrifuges in Natanz as well as the Fordo site indicates Iran is not only seeking to refine its uranium stockpiles, but to expand them as well.
Iran also claimed on Wednesday it would be inserting domestically manufactured fuel rods into a research reactor in Tehran.
Iran has often exaggerated its nuclear achievement claims as part of an propaganda campaign against sanctions, and to gain leverage in its dealings with the West.
Iran insists that the nuclear program is peaceful, but officials in Israel, the United States, Europe, and Gulf Arab capitals all say they believe Iran is seeking nuclear weapons.
A report from the international atomic energy agency in late 2011 cited credible intelligence that Iran had sought - and continued to seek - nuclear technologies of a military nature.
Israeli officials are believed to be mulling a pre-emptive military strike on Iran's nuclear facilities to stop the Islamic Republic from building a nuclear bomb.
Iranian officials, who have repeatedly called for the Jewish state's destruction, have referred to Israel as a "one bomb state."