White House: Window for talks with Iran 'will not remain open indefinitely'

Time is running out for a peaceful resolution to Iran's nuclear program, the White House warned Thursday after a United Nations watchdog accused the country of moving to speed up uranium enrichment.

The warning came as the United States and its partners prepared to meet with Iran next week for the fourth time in 12 months. The United States, Russia, China, France, Great Britain and Germany accuse Iran of running a covert nuclear program for military purposes, which Iran denies.

“What we have said and remains true today is that the window remains open for this to be resolved diplomatically, but that window will not remain open indefinitely,” White House spokesman Jay Carney said.

“We have been very clear with the Iranians about that and we encourage them to come to these talks ready to speak seriously about abiding by their international obligations.”

The International Atomic Energy Agency on Thursday released a report accusing Iran of installing advanced centrifuges at its main uranium enrichment plant. The centrifuges, which the IAEA says aren't yet connected, would enable Iran to speed up production of nuclear fuel that could be used to build a weapon. 

Rep. Chris Van Hollen (D-Md.) called the move “a very alarming development.”

“These upcoming talks really may be the last chance to try to resolve these issues in a peaceful manner,” Van Hollen said Thursday on MSNBC.

The next round talks over Iran's nuclear program will be held on Tuesday in Almaty, Kazakhstan.

State Department spokeswoman Victoria Nuland called the report of centrifuge installations a “further escalation” by Tehran.

“We're obviously concerned that Iran continues to flout its international obligations and has refused to halt its enrichment activities and in fact is taking steps to expand its capacity,” she said. “It already has enough uranium to fuel the Tehran research reactor for at least a decade, and its recent actions would allow it to increase its stockpiles, you know, well beyond the civilian need.

“So this will obviously be a subject that we have to talk about in Almaty, because it's very hard for the international community to understand what Iran is doing when it claims that all of this is peaceful.”

Nuland noted that Iran has ramped up production before nuclear talks in the past.

“I wish I could say ... that this pattern was new, but it isn't,” she said. “We've seen this before, that in advance of diplomatic rounds there're new announcements of activity. It doesn't make it any easier to get where we want to go, which is to have the diplomacy lead to a real process of Iran making it clear to the international community that it's prepared to meet its obligations.”