U.S. President Donald Trump has rejected Iran’s formal counter-proposal aimed at ending the ongoing Middle East conflict, calling Tehran’s reply “totally unacceptable” in a Truth Social post late Sunday.

Iran had submitted its response through Pakistan, which has been acting as a mediator between Washington and Tehran. Trump wrote on Truth Social: “I have just read the response from Iran’s so-called representatives. I don’t like it — TOTALLY UNACCEPTABLE!”

Iran’s semi-official Tasnim News Agency reported that Tehran’s counter-proposal called for an immediate end to the war on all fronts, the lifting of U.S. and international sanctions, a halt to the U.S. naval blockade of Iranian ports, and guarantees against future military attacks on Iran.

The rejection follows the U.S. proposal delivered through Pakistan earlier in the day, which demanded a 12-year freeze on Iran’s uranium enrichment programme and the surrender of 440 kilograms of 60 percent enriched uranium in exchange for gradual sanctions relief and an end to the blockade.

Tehran’s formal response was delivered Sunday through the Pakistani channel, with senior Iranian officials including Mojtaba Khamenei and Supreme National Security Council Secretary Ali Akbar Ahmadian briefed on the U.S. draft before its transmission to President Masoud Pezeshkian.

Trump’s reaction marks another setback in the Pakistan-mediated diplomacy that has so far failed to produce a durable ceasefire. The U.S. naval blockade of Iranian ports remains in force, and Brent crude prices have stayed elevated as markets price in the continued risk premium on the Strait of Hormuz.

Iran has previously rejected earlier U.S. drafts as one-sided, and Trump himself had warned on May 3 that Iran would pay a “big price” if it walked away from negotiations.