TEHRAN — Iran’s chief negotiator said Sunday that Tehran would not agree to any deal with the United States unless it fully secures Iranian rights, as reports emerged that Washington had sent a tougher peace proposal back to Iran. Any tweaks to the proposal could further delay an agreement to formally end the Middle East war and reopen the Strait of Hormuz after weeks of fraught negotiations marked by sharp rhetoric and occasional flare-ups of violence. The New York Times and Axios reported on Saturday that Trump had sent back a new framework to be considered by Iran with “tougher” terms, though details remain unclear. “We will not approve any agreement until we are certain that the rights of the Iranian people have been upheld,” Mohammad Bagher Ghalibaf said, in a video broadcast on state television. Trump has said his priorities include stopping Iran from any nuclear weapon development and re-opening the blockaded Hormuz shipping lane. “The one guarantee that I have to have is that there will be no nuclear weapons. They’ve agreed to that, and it was very interesting,” he told his daug

