WASHINGTON — President Trump said Monday that the month-long cease-fire between the US and Iran “is on massive life support” — but that it’s still in effect as he prepares for a whirlwind trip to China.

Trump, who departs for Beijing on Tuesday, railed against Iran’s “stupid” leaders after receiving an inflammatory peace offer asking that Iran be treated like the war’s winner, with no nuclear concessions.

“It’s on life support,” Trump told reporters during a maternal health event in the Oval Office.

“I would say the cease-fire is on massive life support, where the doctor walks in and says, ‘Sir, your loved one has approximately a 1% chance of living.'”

The cease-fire has been in effect since April 8, though both countries have launched limited attacks during the shaky truce.

Sen. John Fetterman (D-Pa.), an outspoken supporter of Trump’s war with Iran, told The Post that he wanted the president to “keep throttling the Iranian economy” with the naval blockade that began on April 13.

“China deserves to feel that pain,” Fetterman added, referring to Iranian oil exports failing to reach the world’s second-largest economy.

The Pennsylvania Democrat hailed Trump’s demand that Iran surrender about 1,000 pounds of highly enriched uranium, likening the Republican to British wartime leader Winston Churchill.

“Demanding Iran surrender its nuclear material is maximum Churchillian,” Fetterman raved.

A national security official told The Post, however, that Trump hasn’t restarted full-scale fighting for several reasons, including his hope to enlist Chinese President Xi Jinping’s support for a “better deal” that ends Iran’s nuclear ambitions without a drawn-out war.

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China buys about 90% of Iran’s oil exports, giving it significant leverage. 

Trump claimed Monday that Iranian officials confided that only the US and China could retrieve deeply buried uranium due to the logistical complexity of an excavation, hinting at a potential Chinese role in the endgame that could be face-saving for Tehran.

The US official also said Trump hasn’t moved to restart major operations because Gulf Arab allies — including Saudi Arabia, Kuwait, Qatar and possibly Bahrain — indicated they plan to be “more restrictive [over] the use of their airspace and their military bases.”

The Arab nations’ qualms last week quashed Trump’s short-lived “Project Freedom” to reopen the Strait of Hormuz with gunship escorts.

“President Trump doesn’t want the agenda in China to be dominated by Iran,” added Alex Plitsas, senior fellow at the Atlantic Council and a former Pentagon official.

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“He has other economic and national security objectives that he would like to achieve and having the conflict restart while he is there would dominate the headlines and the agenda.”

Plitsas said the lull “leaves a bit more time for any last-minute diplomatic maneuvering to see if they could reach an agreement.”

“The sides are very far apart based on Iran’s response,” he added. “Iran will not be able to take advantage of a few day delay during the president’s trip to China to materially change the battlefield situation.”

John Ullyot, a former National Security Council and Pentagon official, said that Trump “has engaged in and refrained from kinetic action against Iran throughout the conflict based on the situation and his decades of experience as a dealmaker.”

“He clearly has information that no one else does and he’s playing his cards accordingly regardless of his upcoming summit with Xi,” Ullyot said.

Trump claimed Monday that Iranian negotiators agreed “two days ago” to relinquish near weapons-grade enriched uranium, before omitting the provision from the bellicose peace offering.

“They did two days ago. They said, ‘You’re going to have to take it.’ We were going to go with them, but they changed their mind because they didn’t put it in the paper,” Trump said at the Oval Office event.

“They told me, ‘Number one, you’re getting it, but you’re going to have to take it out,’ because the site was so obliterated that there’s only one or two countries in the world that could get it. It’s so deep and got hit so hard that there’s no way they have the equipment to move it. ‘You and China are the only two countries in the world that could take it out.’

“So we talked about it. They said, ‘You’ll have to take it out, because we don’t have the capability of doing it.’”

Trump previously has claimed that Iran agreed to his core war demands only for the Islamic Republic to promptly deny it.

Iranian state media said that the country’s latest peace offer demanded reparations from Washington, a recognition of Iranian sovereignty over the Strait of Hormuz and an end to US sanctions.

“How stupid. Are they stupid people?” Trump said of the offer.

“They think that, well, I’ll get tired of this, or I’ll get bored, or I’ll have some pressure. But there’s no pressure. There’s no pressure at all.”

“We’re going to have a complete victory,” Trump went on. “We’ve already, in theory, had a complete victory from the military standpoint.”

The president said that Iran’s peace negotiations are complicated by a struggle between “moderates” and “lunatics.”