Among those who have warned Trump that the war could be protracted are Vice President JD Vance and Secretary of State Marco Rubio, WSJ's sources say.
They reportedly see a risk that the Iranian regime may continue to resist the U.S. blockade and other military pressure.
The report contradicts Trump's previous statement that he believes the Iran war will be over after the U.S. midterm elections in November this year.
"I believe the war will end immediately after the election," he told reporters on Wednesday, claiming that Iran "cannot hold out any longer."
