A ceasefire meant to facilitate talks to end the war launched by the US and Israel in February has been largely observed, despite occasional exchanges of fire.
Earlier this week, Trump repeated that the war in Iran will be "over quickly".
But Israeli Prime Minister Benjamin Netanyahu said that Iran's stockpile of enriched uranium must be "taken out" before the war against Iran can be considered over.
"There's still enrichment sites that have to be dismantled," Netanyahu said in an excerpt of an interview due to air on CBS's '60 Minutes' show.
Sunday, Iranian President Masoud Pezeshkian did not directly reference the proposal but said: "We will never bow our heads before the enemy, and if talk of dialogue or negotiation arises, it does not mean surrender or retreat."
Trump posted on Truth Social: "I have just read the response from Iran's so-called 'Representatives.' I don't like it - TOTALLY UNACCEPTABLE."
US news outlet Axios reported that the one-page, 14-point US memorandum includes provisions such as a suspension on Iranian nuclear enrichment, the lifting of sanctions, and restoring free transit through the Strait of Hormuz. BBC reported.
It cited two US officials and two other sources - all unnamed - whom it described as briefed on the issues. These sources were reported as saying that many of the terms laid out in the memo would be contingent on a final agreement being reached.
