The U.S., Iran and a group of regional mediators are discussing the terms for a potential 45-day ceasefire that could lead to a permanent end to the war, according to four U.S., Israeli and regional sources with knowledge of the talks.

Why it matters: The sources said the chances for reaching a partial deal over the next 48 hours are slim. But this last-ditch effort is the only chance to prevent a dramatic escalation in the war that will include massive strikes on Iranian civilian infrastructure and a retaliation against energy and water facilities in the Gulf states.

Driving the news: President Trump's 10-day deadline to Iran was expected to expire Monday evening. But on Sunday, Trump extended his deadline by 20 hours and posted on Truth Social a new deadline of Tuesday at 8pm ET.

Trump told Axios on Sunday that the U.S. is "in deep negotiations" with Iran and that a deal can be reached before his deadline expires on Tuesday.
"There is a good chance, but if they don't make a deal, I am blowing up everything over there," he said.

Trump has threatened to destroy infrastructure that is vital to Iranian civilians if he is unable to reach a deal with the regime.

Such attacks could constitute war crimes, and Iran has threatened to retaliate with attacks against infrastructure in Israel and the Gulf states.
Two sources said the operational plan for a massive U.S.-Israeli bombing campaign against Iran's energy facilities is ready to go, but stressed the extension of Trump's deadline was aimed at giving a last chance to reach a deal.

Behind the scenes: Four sources with knowledge of the diplomatic efforts said the negotiations are taking place through Pakistani, Egyptian and Turkish mediators and also through text messages sent between Trump's envoy Steve Witkoff and Iran's Foreign Minister Abbas Araghchi.

A U.S. official said the Trump administration gave Iran several proposals in recent days, but so far Iranian officials hadn't accepted them.
The sources said the mediators are discussing with the parties the terms for two-phased deal; the first phase would a potential 45-day ceasefire during which a permanent end to the war would be negotiated.
The ceasefire could be extended if more time were needed for talks, one of the sources said.
The second phase would be an agreement on ending the war.
The sources said mediators think that fully reopening the Strait of Hormuz and a solution for Iran's highly enriched Uranium — either through its removal from the country or dilution — could only be a result of a final deal.

Zoom in: The mediators are working on confidence building measures Iran could do regarding the reopening of the strait of Hormuz and it highly enriched Uranium stockpile, the sources said.

These two issue are Iran's main bargaining chips in the negotiations and the Iranians will not agree to fully give up on them for only 45 days of ceasefire, two of the sources said.
The mediators want to see whether Iran could take partial step on both issues in the first phase of the deal. They are also working on steps the Trump administration could take to give Iran guarantees that the ceasefire will not be temporary and that the war will not resume.
The Iranian officials made clear to the mediators they don't want to be caught in a Gaza or Lebanon situation where there is a ceasefire on paper, but that the U.S. and Israel can attack again whenever they want to.
The mediators are also working on other U.S. confidence-building measures the U.S. could take that would address some of Iran's demands.
The White House declined to comment.

What to watch: A source with direct knowledge said the the mediators are highly concerned that the Iranian retaliation for a U.S.-Israeli strike on the country's energy infrastructure would be destructive for Gulf countries' oil and water facilities.

The mediators told the Iranian officials there is no time for further negotiation tactics and stressed the next 48 hours are the last opportunity for them to reach a deal and prevent massive destruction for the country.
The Iranian officials, at least in public, are still taking an extremely hard line and rejecting any concessions. The Iranian revolutionary guards corps navy said Sunday the situation in the Strait of Hormuz will "never return" to what it was before the war, especially for the U.S. and Israel.