Iranian sources earlier on Monday said the proposal would set aside discussion of Iran's nuclear program until the war has ended and disputes over shipping from the Gulf are resolved.
A US official said on Monday that President Donald Trump is unhappy with an Iranian proposal because it did not address Iran's nuclear program.
"He doesn't love the proposal," the US official said, referring to Trump.
Earlier in the day, Trump discussed the proposal with his top national security aides. The US-Iran conflict remains in a stalemate, with energy supplies from the region reduced.
Dispute over nuclear issues
Iranian sources earlier on Monday said the proposal would set aside discussion of Iran's nuclear program until the war has ended and disputes over shipping from the Gulf are resolved. Washington has said nuclear issues must be dealt with from the outset.
Work to bridge gaps between the US and Iran has not halted, sources from mediator Pakistan have said.
But hopes of reviving peace efforts have receded since Trump announced this weekend he had scrapped a visit by his special envoy Steve Witkoff and son-in-law Jared Kushner to Islamabad, the Pakistani capital.