Iran and the UN atomic watchdog were tight-lipped on Monday after talks aimed at improving transparency and clearing up long-standing allegations of Tehran's past efforts to develop nuclear weapons, AFP reports.
The International Atomic Energy Agency (IAEA) said only that "progress was reviewed on the implementation of practical measures (to be taken by Iran)...agreed three months ago," according to the news agency.
Its statement "noted that Iran has taken several actions and that some related work continues. Discussions on additional practical measures to be implemented in the next steps are ongoing."
Iran's delegation, led by Iranian ambassador to the IAEA Reza Najafi, left the talks without speaking to reporters. Neither side said when the next meeting might take place.
The meeting comes ahead of the next round of parallel but linked talks this week, also in Vienna, between Iran and the five permanent members of the UN Security Council plus Germany.
The talks in Vienna are a follow-up to the interim agreement reached between Iran and the West several months ago, under which Iran committed to limit its uranium enrichment to five percent, halting production of 20 percent-enriched uranium.
In return, Iran is gradually winning access to $4.2 billion of its oil revenues frozen abroad and some other sanctions relief.
Iran and the six powers want to turn the November deal into a lasting accord by July. As part of the first phase of the deal, UN experts visited the heavy water plant at the unfinished Arak reactor on December 8, when all of the IAEA's "technical objectives" were met, said the Vienna-based agency.
Meanwhile, French Foreign Minister Laurent Fabius said Monday at the start of a visit to Washington that "France is determined to look for a long term diplomatic solution to the Iranian nuclear crisis."
He cautioned, however, that did "not mean, obviously, that we are ready to accept any solution."
"Discussions on enrichment are and will be difficult," Fabius told an American Jewish lobby group, AJC Global Jewish Advocacy, according to AFP.
"But our line is clear: a demanding approach is the only way to verify the exclusive peaceful purpose of the program," he added.
"France is ready for an agreement, but it is clear that we shall not allow Iran to obtain nuclear weapons," the French minister added.
The IAEA has long been seeking answers from Iran over what it calls "overall, credible" evidence that before 2003, and possibly since, Tehran has conducted research into making nuclear weapons.
The Islamic Republic has rejected such claims, saying they are based on faulty intelligence from the CIA and Israel's Mossad that it has not been allowed to see.
According to an IAEA report from March, Iran was sticking to a partial nuclear freeze as agreed upon in the interim deal and, last week, the IAEA said it had received an explanation from Iran about the development of detonators that can help set off an atomic explosive device.