The six nations had asked the Iranians to respond concretely to their demand to curb higher-level enrichment. While Mann said that topic was "addressed," he refused to qualify whether the Iranian response met the expectations of the world powers.
While the Islamic Republic has previously mentioned lifting sanctions or postponing pending ones, one of the diplomats said Monday's request for "sanctions relief" was the most direct to date. That appeared to reflect the mounting pain caused by accumulating sanctions, particularly international embargoes on Iran's oil sales.
In addition to longer-term U.N. and other sanctions, Tehran is now being squeezed by the widening international embargo on its oil sales, which make up more than 90 percent of its foreign currency earnings.
Sanctions levied by the U.S. have already cut exports of Iranian crude from about 2.5 million barrels a day last year to between 1.2 and 1.8 million barrels now, according to estimates by U.S. officials. An EU embargo on Iranian crude that starts July 1 will tighten the squeeze.
Comments by Ali Bagheri, the No. 2 on the Iranian delegation, reflected the gap between the two sides' priorities.
"We elaborated in detail ... the illegality of referring Iran's nuclear issue to the U.N. Security Council and issuance of U.N. Security Council resolutions," he told reporters, referring to Security Council demands — enforced by sanctions — that Iran stop enriching.
The six nations formally are only prepared to ease restrictions on airplane parts for Iran's outmoded, mostly U.S.-produced, civilian fleet and are offering technical help with aspects of Iran's nuclear program that cannot be used for military purposes.
While not budging on lifting existing sanctions or those already decided upon, diplomats familiar with the talks told The Associated Press that the six are also prepared to guarantee that no new U.N. penalties will be enacted if Tehran compromises enough. The diplomats demanded anonymity because that possible offer has not yet been formally made.
For Iran, the main formal demand remains international recognition of its right to enrich and related issues — with increasing emphasis on sanctions relief.
The six also want Fordo, the underground Iranian facility where most of the higher-level enrichment is taking place, shut down and for Iran to ship out its higher-grade stockpile. Fordo is of special concern because it might be impervious to air attacks, a possible last-resort response to any Iranian bomb in the making.
Associated Press writer Vladimir Isachenkov contributed from Moscow.
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