UNITED NATIONS  - President Barack Obama’s decision not to issue US visa to Iran’s choice for UN ambassador has raised concerns among diplomats here about possible precedents, such as calls from US interest groups for future visas to be denied for political reasons, or retaliation broad, as the issue is set to figure at the United Nations.

Rejecting the US decision, Iran has pledged to take up the case directly with the UN, saying it would insist on its candidate for the post, Hamid Abu Talebi.

The United States, which hosts the United Nations, said Ambassador Abutalebi was unacceptable given his role in a 444-day crisis in which radical Iranian students stormed the US embassy in Tehran and took 52 Americans hostage.

A spokesman for Iran’s mission to the United Nations said the White House decision was unfortunate and may violate international law.

“It is a regrettable decision by the US Administration which is in contravention of international law, the obligation of the host country and the inherent right of sovereign member states to designate their representatives to the United Nations,” spokesman Hamid Babaei said in a statement.

The United Nations said it had no comment at this time on the US decision. “We haven’t been dealing specifically with this case right now” and it remains an issue between the US and Iran, Farhan Haq, UN deputy spokesman, told reporters on Friday in New York. “If there’s a need for us to have a role down the line, we’ll consider it.

The US decision leaves it at odds with the commitment it made to the United Nations in 1947 to provide unimpeded entry to UN headquarters in New York to the diplomats that UN member states choose to assign there.  “If the US starts to pick and choose who can represent other

countries at the UN, other countries are likely to react angrily. How would Washington feel if Switzerland vetoed its choice for American ambassador to the Human Rights Council in Geneva?” Richard Gowan, an international relations expert at New York University, said.

The decision also comes in the midst of Obama administration efforts to seize the election of moderate Iranian President Hassan Rouhani last June to reverse decades of antagonistic relations with Tehran. The US and five other world powers are currently in negotiations with Iran to try to resolve diplomatically the issue of Iran’s nuclear programme, which the west claims is weapon-oriented.

Iran had already made clear its view that any effort to block Abutalebi from entering the US to take up his UN post would be “unacceptable.” The Iranian Foreign Ministry, noting Abutalebi has served as Iran’s ambassador to Australia, Belgium, Italy, and the European Union, called him “one of Iran’s most qualified diplomats.”

The collision between Iran and the US Congress had left Obama with two unpalatable choices: violate the 1947 “Headquarters Agreement” the US reached with the nascent UN, or defy a unanimous Congress.

The Obama administration, amid the complex negotiations over Iran’s nuclear program, has been labouring to convince a dubious Congress that it is toeing a hard line with Tehran. It clearly wishes the choice of Abutalebi had not been made in the first place.

“Our preference certainly would have been that he wouldn’t have been nominated to begin with,” State Department spokeswoman Jen Psaki said earlier this week.

“If he (Obama) doesn’t accept the ambassador, then he runs into problems with the Iranians,” said Anthony Cordesman of the Center for Strategic and International Studies, a Washington policy research organization. “If he does accept the ambassador, he’s soft on Iran.”

Cordesman said he knew of no legal precedent for Congress to block an ambassador or issuance of a visa, a responsibility left to the executive branch.

Some of the same legal questions came up in 2005 when Iran applied for a visa for then-President Mahmoud Ahmadinejad to address the UN and they apply to Aboutalebi’s visa application, an expert said. Ahmadinejad was representative of a UN member state as would be Aboutalebi, he said.

The Department of Homeland Security initially found Ahmadinejad ineligible for a visa to enter the US because of suspicions he participated in the embassy seizure, only to have the State Department grant it months later after interviewing former hostages.

Former President Jimmy Carter, who lost his re-election bid, in part, because of the hostage crisis, said in an interview with Washington radio station WTOP last week that he favored letting Aboutalebi take the UN post.

“You know, those were college students at that time, and I think that they have matured,” Carter said. “I think it would be inappropriate for the United States to try to block someone that Iran wanted to choose.”

The UN’s Committee on Relations with the Host Country, established in 1971, governs relationships between countries where envoys are sent and the countries that send them. That committee has 19 member countries including the US, Cuba, Iraq and Libya. Iran is not a member.

The agreement prohibits the US from imposing “any impediments to transit” to or from the UN headquarters. The State Department has suggested there are exceptions to the agreement. UN delegates to the US from Iran, North Korea, Cuba and now Syria are allowed into a limited zone around the United Nations building in New York and are restricted from other travel in the US.

Reuters add: Iran has called off a deployment of warships to the Atlantic Ocean, the semi-official Fars news agency said on Sunday, shelving plans for its vessels to approach US maritime borders in response to the US navy’s presence in the Gulf.

A senior Iranian naval commander was quoted in February as saying that several warships would be sent towards US maritime borders in the Atlantic although the Pentagon said at the time that it was not concerned and that many countries operated in the ocean’s international waters.

But on Sunday, Fars quoted Navy commander Admiral Habibollah Sayyari as saying: “Due to a change in schedule, the battle Group-29 of the naval forces of the Iranian navy will not head to the open waters of the Atlantic Ocean and the mission will possibly be given to another group.”

He gave no reason for the decision but said warships’ missions were likely to change “depending on the situation in the region”, such as a rise in piracy in the Gulf of Aden.

“So (the) Group-29, which consists of the Sabalan destroyer, Khark logistics carrier and two helicopters... will not go to the Atlantic Ocean and will return home within days,” Sayyari was quoted as saying.

The United States and its allies regularly stage naval exercises in the Gulf, saying they want to ensure freedom of navigation in the waterway through which 40 percent of the world’s seaborne oil exports passes.

Iran, whose entire 1,800 km (1,120 miles) southern border runs along the Gulf and the adjacent Gulf of Oman, has often said it could block the Strait of Hormuz, which connects the two waters, if Tehran came under military attack over its disputed nuclear programme.

AFP adds: Iranian nuclear chief said Sunday that the country would need 30,000 of its new generation centrifuges to meet domestic fuel demands, far more than the current number.

Ali Akbar Salehi’s comments came just days after the latest round of international talks in Vienna aimed at securing a long-term deal over Iran’s disputed nuclear programme.

The capability and number of centrifuges at Tehran’s disposal has been a key concern among countries which suspect the Islamic republic’s eventual goal is to build an atomic bomb.

Iran currently has nearly 19,000 centrifuges, including 10,000 of the so-called first generation being used to enrich uranium.

The country insists its nuclear activities are solely for civilian purposes. “If we want to use the Natanz enrichment facility to produce the annual fuel of Bushehr nuclear power plant, we need to build 30,000 new centrifuges,” Salehi was quoted by the Fars news agency as saying.

Under an interim agreement reached last year that expires on July 20, Iran froze key parts of its nuclear programme in return for limited sanctions relief and a promise of no new sanctions.

Under the deal, Iran cannot increase its number of centrifuges, but in February it announced it was developing new ones that are 15 times more powerful than those currently used.

Any final deal with the West may involve Iran slashing its number of centrifuges, changing the design of a new reactor at Arak and giving UN inspectors more oversight.

The Bushehr plant, which produces 1,000 megawatts of electricity, came into service in 2011 after several delays blamed on technical problems. Tehran took control of the plant from Russia last year.

In October, Salehi said Iran had built a fuel production line for its sole nuclear power plant which would go on stream within three months.

However, he did not specify a date after which Iran could use locally produced fuel instead of that provided by Russia.

Iran has said it wants to produce 20,000 megawatts of electricity from nuclear power, which would require building 20 reactors.