The State Department says the international community's patience with Iran is limited, and that another meeting of the P5+1 grouping will be held shortly to take up the pressure side of its two-track approach to Iran of incentives if it cooperates on the nuclear issue, and penalties if it doesn't.
The comments follow a meeting of senior diplomats of the six powers in Brussels Friday who reviewed Iran's equivocal reaction to a proposal under which most of its stockpile of enriched uranium would be sent abroad for reprocessing and returned to fuel a medical research reactor in Tehran.
Iran's chief nuclear negotiator appeared to accept the plan, developed by the International Atomic Energy Agency (IAEA), at a meeting with the P5+1 in Geneva October first in a move that would have eased concerns that its enrichment program is weapons-related.
But the Tehran government has since backtracked on the issue, with Foreign Minister Manouchehr Mottaki saying this week Iran is no longer willing to send the uranium out of the country.
At a news briefing Friday, Deputy State Department Spokesman Robert Wood expressed frustration over the Iranian stance.
"This is something the Iranians agreed to in principle," said Robert Wood. "If you remember back in the Geneva meeting they agreed in principle to this proposal that was brought about under the auspices of the IAEA. And since then Iran has had a difficult time saying yes to this proposal. So we're hopeful that Iran will, but should it not, we will obviously take a look at the pressure side of our dual-track approach."
Among the P5+1 members, Russia and China have been resistant to punitive action against Iran such as new U.N. sanctions.
Spokesman Wood stopped short of predicting that the grouping's next meeting on Iran, at a date and venue still to be determined, would produce decisions on penalties. But he said the six powers are of one mind on the two-track approach.
President Barack Obama said in the South Korean capital, Seoul, early Thursday that he expects a package of potential steps to be developed over the next several weeks that will, as he put it, indicate our seriousness to Iran.
A senior State Department official who spoke to reporters Friday said the President still expects to be able to decide by year's end if a diplomatic solution to the Iranian nuclear issue is possible though he said it is not a hard deadline.
The same official said there is great concern among member countries of the IAEA governing board about Iran's conflicted response to the agency proposal, which he said could reflect a split in the Iranian leadership.