CNN — Iran has begun installing advanced new centrifuges at its main uranium enrichment site at Natanz that are capable of accelerating production of fuel for a nuclear weapon, a move that senior U.S. officials warned could jeopardize upcoming talks aimed at curbing Iran's nuclear ambitions.
The disturbing revelation comes as the "P5 plus one" diplomatic bloc of countries is preparing to offer a package of incentives to Iran to close its underground facility at Fordow and ship out its stockpile of uranium already enriched to a high purity level of 20%.
"This can't help the talks," a senior US official said.
The P5 plus one bloc consists of the United States, Britain, France, Germany, Russia and China.
Last month, Iran announced its intention to use the new machines and last week said it was already beginning to install them. Officials said inspectors from the International Atomic Energy Agency found a significant number of the upgraded centrifuges installed when they visited the site days earlier. The finding is expected to be confirmed in an IAEA report to be released Thursday, officials said.
Experts said the new, advanced centrifuges will allow Iran to enrich uranium at a rate three to five times greater than their old machines, thereby increasing its stockpile more quickly.
"It's disturbing because they are sending a signal that they are trying to dramatically increase their enrichment capacity," said David Albright, president of the Institute for Science and International Security, a nonprofit group that informs about international security issues. "We have no way of knowing if they will work, but the worry is that Iran could sneak out and enrich enough uranium to build a bomb."