VIENNA, Austria – Iran has met a key demand of the U.N. nuclear agency by delivering blueprints that show how to mold uranium metal into the shape of warheads, diplomats said Tuesday, in an apparent concession meant to stave off the threat of new U.N. sanctions.

But the diplomats said Tehran has failed to meet other requests made by the International Atomic Energy Agency in its attempts to end nearly two decades of nuclear secrecy on the part of the Islamic Republic.

The diplomats spoke to The Associated Press as IAEA chief Mohamed ElBaradei put the finishing touches on his latest report to the agency’s 35-nation board of governors, for consideration during a meeting that begins on Nov. 22, Thanksgiving Day.

The confidential report, expected to be distributed to agency members this Wednesday or Thursday, is likely to show substantial but not full compliance by Iran with its pledges to come clean on past activities – and confirm at the same time that Tehran continues to enrich uranium in defiance of the U.N. Security Council.

Those findings will likely lead to new calls by the United States, France and Britain for a third round of U.N. sanctions. But China and Russia, the other permanent Council members, may emphasize progress made,and demand more time for Iran before fresh U.N. penalties are imposed.

The agency has been seeking possession of the blueprints since 2005, when it stumbled upon them among a batch of other documents during its examination of suspect Iranian nuclear activities. While agency inspectors had been allowed to examine them in the country, Tehran had up to now refused to let the IAEA have a copy for closer perusal.