Iran's chief negotiator warned overnight that the United States was not to be trusted, saying his government would not agree to any deal with the US unless it fully secured Iranian rights.Mohammad Bagher Ghalibaf's remarks came as reports emerged that US President Donald Trump had sent a tougher peace proposal back to Iran, and underlined the rift that the parties still need to close.Any tweaks to the draft 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.Iran was already in talks with the US about its nuclear program in February when the US and Israel launched air and missile strikes that wiped out much of the country's senior leadership Iran was also in negotiations with the US in June 2025 when the US attacked its nuclear facilities.Iran has long insisted that its nuclear program is for purely civilian ends, while the US and its allies say it aims to develop a weapon.US media outlets — The New York Times and Axios — reported on Sunday AEST that Trump had sent back a "tougher" new framework for Iran to consider, though details remain unclear.Trump has said his priorities include stopping Iran from developing any nuclear weapons and reopening the Hormuz shipping lane, which Iran has blockaded since the war began."The one guarantee that I have to have is that there will be no nuclear weapons