WASHINGTON (Reuters) -- World powers failed to agree on Tuesday on final elements of a new UN sanctions resolution against Iran over its nuclear program, but the United States hopes to get a deal within weeks, the State Department said.

Senior officials from the United States, China, Russia, Germany, France, and Britain spoke via conference call for about 1-1/2 hours and were still working on finalizing the sanctions resolution, said State Department spokesman Sean McCormack.
""It was a good, constructive phone call. We're not there yet. But our hope ... is that in the coming weeks that we could have a resolution that is voted on in the Security Council,"" McCormack told reporters.
Last week, a U.S. national intelligence estimate said Iran had no nuclear weapons program, a surprise announcement that increased reluctance among already skeptical Russia and China for a third round of UN Security Council sanctions against Iran.
McCormack, who declined to provide details about the new resolution or say whether Russia or China supported it during the conference call, said the intelligence estimate did not mean a change in strategy or tactics over Iran.
""What is very interesting about this is that we're not talking about whether or not there's going to be a resolution, but we're talking about what are the elements to a new Security Council resolution,"" he said, adding that the senior officials planned another conference call very soon.
There had been a possibility that U.S. Secretary of State Condoleezza Rice would meet ministers from the permanent members of the UN Security Council plus Germany in Paris this weekend, but U.S. officials said this was unlikely.
""I wouldn't expect that they will. And certainly if the ministers need to get together, they can do so via conference call,"" said McCormack, when asked whether there would be a meeting to discuss Iran on the sidelines of a donors conference for the Palestinians in Paris.
Two rounds of sanctions have already been imposed on Iran for failing to halt uranium enrichment.
Iran insists it wants only fuel for power plants and that it is not building a nuclear bomb.