DUBAI, United Arab Emirates (AP) — U.S. President Donald Trump on Monday said the Iran ceasefire is on “life support” after he rejected Tehran’s latest proposal to end the war. Officials said the proposal included some concessions on Iran’s disputed nuclear program, but Trump dismissed it as “garbage.”

The stalled diplomacy and recent exchanges of fire could tip the Middle East back into open warfare and prolong the worldwide energy crisis sparked by the conflict, with Iran’s chokehold on the Strait of Hormuz and America’s blockade of Iranian ports still in place.

Asked at an unrelated White House event if the ceasefire was still in place, Trump said it’s “unbelievably weak” and on “life support.”

“I would call it the weakest right now after reading that piece of garbage they sent us,” Trump added. “I didn’t even finish reading it.”

Trump is expected to use a trip this week to China to urge President Xi Jinping to pressure Iran. Beijing is the biggest buyer of Iran’s sanctioned crude oil, giving it leverage.

But the U.S. and Iran remain far apart on a host of issues. Trump has demanded a major rollback of Iran’s nuclear activities, while Iran is pushing for a more limited agreement that would reopen the strait and lift the blockade ahead of further negotiations.

Two regional officials told The Associated Press that Iran has offered to dilute part of its highly enriched uranium and transport the rest to a third country. Russia has previously offered to take it. The officials spoke on condition of anonymity to discuss the sensitive diplomacy.

Trump has demanded that the nuclear material be removed completely, and is unlikely to accept other Iranian proposals for the formalization of its control of the strait and for U.S. reparations.