U.S. Says Iran was 'Interested' by Nuclear Talks Proposal

Iran was "interested" by updated proposals from world powers to break a stalemate over its suspect nuclear program, and must now take concrete steps to move forward, a U.S. official said Wednesday.

Characterizing two-day talks in Kazakhstan as "useful," State Department acting deputy spokesman Patrick Ventrell said "the onus is absolutely on Iran."

But he added: "We welcome that... Iran was interested in our ideas, is going to come back to the table here, and we'd like to see them take some of the concrete steps they need to come in line with the international community's concerns."

Iran and the five permanent members of the U.N. Security Council -- the United States, China, Russia, Britain and France -- plus Germany, agreed Wednesday to hold new talks in March and April on the Islamic republic's disputed nuclear drive.

The latest meeting saw the leading powers, known as the P5+1, offer Iran a softening of non-oil or financial sector-related sanctions in exchange for concessions over Tehran's sensitive uranium enrichment operations.

Iran's Foreign Minister Ali Akbar Salehi, speaking in Vienna, said he was "very optimistic about the outcome" of the process.

"Things are taking a turning point and I think the Almaty meeting will be (seen as) a milestone," Salehi said.

Ventrell refused to be drawn on the details of what he called "an updated and serious proposal" to Iran to try to break the deadlock over what the West believes may be a covert bid to obtain a nuclear bomb.

He acknowledged there had been no breakthroughs in Almaty, but added that "time will tell if they're going to come back and take some of these confidence-building measures on their part so that diplomacy can continue."

The P5+1 agreed to meet again at the level of senior civil servants on March 17-18 in Istanbul, and then with chief negotiators in Almaty on April 5-6.

"It's really at the technical level where we can flesh out exactly what we expect -- they know what we expect -- but where we can flesh this out in great detail," Ventrell said.

The offer reportedly involves easing crippling sanctions on Iran's gold and precious metals trade and lifting some very small banking operations.

In return, it demands a tougher weapons inspection regime and the interruption of enrichment operations at the feared Fordo bunker facility where 20-percent enrichment goes on.