VIENNA—As international talks on Iran were about to resume, the Obama administration early this month secretly presented an eight-page document to Tehran in a bid to demonstrate Washington’s flexibility and offer an opening to end the protracted dispute over Iran’s nuclear program.

But a week later, the chairman of the Iranian parliament’s nuclear committee went public with the Nov. 9 proposal, slamming it by saying the U.S. had brought the negotiations “back to zero.”

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