Bushehr nuclear power plant
Bushehr nuclear power plant AFP photo

The United States said on Wednesday it was seeing "troubling developments" in Iran's nuclear program and called on the country's new president to take concrete steps soon to ease concerns about Tehran's aims, Reuters reports.

Reinforcing the West's message at a meeting of the UN nuclear watchdog that time was of the essence in moving to resolve the decade-old nuclear dispute, the European Union told Tehran that any "further procrastination is unacceptable."

Both the United States and the EU expressed hope that the election of Hassan Rouhani, who has been described by the West as a relative moderate, would lead to a softening of the Islamic Republic’s nuclear defiance.

At the same time, they also said Iran had continued to increase its nuclear capacity in recent months and that no progress had been made so far in a long-stalled UN investigation into suspected atomic bomb research by Iran, which denies any such activity.

They warned that they may seek diplomatic action against Iran at the next quarterly meeting of the 35-nation board of the UN's International Atomic Energy Agency (IAEA), in late November, if no progress has been achieved by then.

U.S. Ambassador Joseph Macmanus said Washington was ready to work with the new Iranian government "to reach a diplomatic solution that will fully address the international community's concerns" about Iran's nuclear program.

"We are hopeful that the Rouhani administration will live up to its assurances of transparency and cooperation by taking concrete steps over the next several months," he told the closed-door board meeting, according to a copy of his speech quoted by Reuters.

But, Macmanus added, "Should Iran continue its intransigence and obfuscation, we will work with fellow board members at the November board meeting to hold Iran appropriately accountable."

Rouhani, who succeeded Mahmoud Ahmadinejad, has pledged moderation in Iran's foreign and domestic policies and called for "constructive interaction" with the world. At the same time he made it clear that Iran will not give up "one iota" of its nuclear rights.

Rouhani said on Tuesday he would meet with the foreign ministers from some of the six powers - Russia, China, France, Britain, the United States and Germany - when he attends the UN General Assembly in New York this month.

He also said that the time for resolving Iran's nuclear dispute with the West was limited, urging the world to seize the opportunity of his election.

Iran's Foreign Minister Mohammad Javad Zarif, tasked with leading nuclear negotiations, said on Wednesday Iran's nuclear work ought to be operated transparently and under international safeguards, but world powers could not "wish it away".

"Getting to yes is our motto ... but it takes two to tango," he said in a live interview on Iranian broadcaster Press TV.

Iran's last round of talks with the big powers - the five permanent members of the U.N. Security Council plus Germany, dubbed the P5+1 - was in April in Kazakhstan, before Rouhani's election, and both sides have said they want to continue soon.

"If the United States and the rest of the P5+1 group are not prepared to get seriously involved in this process then it will be a totally different scenario," Zarif said in English.

Zarif and EU foreign policy chief Catherine Ashton are set to meet in New York later this month to discuss restarting negotiations over Iran’s nuclear program.

An IAEA report released at the end of August found that Iran has further boosted its capacity for uranium enrichment.

The report said that Tehran has now installed more than 1,000 advanced centrifuges at its Natanz enrichment plant.

Citing the IAEA's latest report on Iran, Macmanus said, "These are concerning escalations of an already prohibited activity," according to Reuters.

Iran was also making further progress in the construction of the Arak reactor, which can yield plutonium for bombs, including putting the reactor vessel in place and beginning to make fuel.

"All of these are troubling developments," Macmanus added.