UNITED NATIONS -- Six months after President Barack Obama made a groundbreaking phone call to his Iranian counterpart, Hassan Rouhani, the administration has made clear that a complete thaw in relations between Iran and the United States is premature.
The latest reminder is the appointment of Hamid Aboutalebi, a veteran Iranian diplomat who is Tehran's choice as United Nations envoy, and who once played a still-mysterious role in the 1979 hostage crisis.
"We think this nomination would be extremely troubling," State Department spokeswoman Marie Harf told reporters Wednesday. "We're taking a close look at the case now, and we've raised our serious concerns about this possible nomination with the government of Iran."
Mr. Aboutalebi's visa has been pending for at least two months. For the past 35 years, it has been customary for the United States to disallow anyone known to be affiliated with the Iranian student movement that held Americans hostage for 444 days.
The visa holdup, first reported by Bloomberg News this week, is one of many efforts by Washington to put pressure on Iran, even as it negotiates with the Rouhani government over its contentious nuclear program. The United States last week supported renewal of a U.N. human rights monitor for Iran. It has pressed a separate U.N. committee to investigate reports that Iran is supplying weapons to Gaza militants.
Samantha Power, the U.S. ambassador to the U.N., said at a congressional hearing Wednesday that the Iranian economy "is in the vise of sanctions," which the Obama administration, she said, has no plans yet to lift. "We share your skepticism," she told a House Appropriations Committee hearing. "We share your lack of trust."
Mr. Aboutalebi's connections to the group responsible for the hostage-taking, known as the Muslim Students Following the Imam's Line, have been impossible to keep secret in the Internet age. His picture is part of an online photo gallery of members.
Mr. Aboutalebi said in an interview in early March that he was an occasional interpreter for the group, but was otherwise uninvolved. "Once or twice, I helped in translation in English or French," he told the website Khabar Online.
A former leader of the hostage-taking group, Ibrahim Asgharzadeh, said Mr. Aboutalebi was not among the leaders of the group that took over the U.S. Embassy in Tehran -- "the den," he called it -- nor among its stable of regular interpreters.
Mr. Asgharzadeh has become a reformist politician since then and has served brief stints in jail for speaking out against Iran's hard-liners.
"On the whole, I think the hard-liners are trying to hold up the progress of President Rouhani's diplomatic team and make obstacles by making up the story that Mr. Aboutalebi was one of us hostage takers," Mr. Asgharzadeh said by phone from Mashhad, his hometown in Iran.
Mr. Aboutalebi, 56, studied at the Sorbonne and served as Iran's ambassador to Australia, Belgium and Italy before joining the political office of Mr. Rouhani last October. He was part of his government's delegation to the General Assembly meeting in 1994.
The State Department is obliged to let even its most strident critics come to U.N. meetings -- which explains the visits of Mr. Rouhani's predecessor, Mahmoud Ahmadinejad -- but visa rules for diplomats based in New York City fall under different rules.
In a measure of the wide gulf that remains between Iran and the United States., an Iranian lawmaker, Mehdi Bazrpash, said Wednesday that the visa delay represented the latest U.S. insult against Iran. "It is not fitting for our country that our chosen envoy to the United Nations is not accepted by America," he said, according to the Fars News Agency.
At the same time in Washington, Sen. Ted Cruz, R-Texas, who has led congressional expressions of outrage this week over Mr. Aboutalebi's appointment, introduced legislation that his office said was meant "to prevent known terrorists from obtaining visas to enter the United States as ambassadors to the United Nations."