The official, whose name was not reported, spoke in Geneva, Switzerland, as the five permanent members of the U.N. Security Council -- the United States, Britain, France, Russia and China -- plus Germany, collectively known as the P5-plus-one, prepared to begin a new round of talks Thursday, Haaretz reported.
The official said the P5-plus one would require a suspension of nuclear operations long enough to allow for negotiation of a comprehensive resolution, and the suspension would have to cover "all the components of the Iranian nuclear program," including enrichment and stockpiling of uranium, among other considerations, and allow for international monitoring.
"What we're looking for is a first phase, a first step, an initial understanding that stops Iran's nuclear program from moving forward and rolls it back for first time in decades," the official said.
He said the powers would offer "very limited, temporary, reversible sanctions relief" from sanctions in return.
The official said it would be counterproductive for Congress to strengthen sanctions against Iran, suggesting that would undermine the talks.