Russia said on Thursday it is trying to firm up plans for a new round of talks this month between global powers and Iran over Tehran's nuclear program, which the West suspects is aimed at developing a nuclear weapons capability.

Iranian news agency ISNA said on Wednesday that Iran and six world powers would resume talks in late January, but a European Union official said that the two sides had yet to agree a date. No venue has been agreed.

"Russia is concerned about this and we continue to work, including with our Iranian partners, to resolve this issue as soon as possible," Russian Deputy Foreign Minister Sergei Ryabkov said, according to state-run news agency Itar-Tass.

Ryabkov, Russia's negotiator at the talks, said that until there is a final agreement "there is no agreement."

The Russian Foreign Ministry said later that there was an understanding among the parties involved that the meeting should take place this month, and that the dates reported by ISNA, January 28-29, were being discussed.

But it said the dates could change if there is no agreement on the venue, and added that Russia was open to any venue.

Senior UN nuclear inspectors were in Iran for a second day of talks on Thursday, seeking to unblock a long-stalled investigation into suspected atomic bomb research in the Islamic state.

But diplomats in Vienna said Thursday they had received no indication from the International Atomic Energy Agency (IAEA) delegation on whether real progress was being made at the meeting in Tehran, the latest in a year of attempts by both sides to secure a deal.

"We don't want to speculate at this point on what the extension into a second day might mean," one Western envoy told AFP, wishing to remain anonymous.

A second said the extension was "more a sign that they need more time to discuss in the only place that both sides can have the authority to agree anything."

The IAEA declined to comment.

ISNA said "technical discussions" on Wednesday had focused on finding "a solution to concerns and questions raised by the IAEA."

Earlier, Admiral William Fallon, the former head of US Central Command which covers the Middle East, said on Wednesday that Iran posed concerns for both the US and Israel but voiced hope for a diplomatic solution to the nuclear row.

"If the US were to put a full-fledged strike campaign in there, that would probably take several weeks, it could put this program back for several years," Fallon said at the American Security Project, a research group.

Israel, which has not ruled out military action, has less capability than the US and would face a more difficult task than in 1981 and 2007 when it secretly bombed nuclear sites in Iraq and Syria, Fallon said.

Iran's suspected nuclear facilities are not a "pinpoint target" but are instead dispersed and largely underground, he said.

"The bottom line is, it's not going to be a one-time shot. It's not going to be like 1981 or even 2007," Fallon said.

Reuters - AFP