Several advisers close to U.S. President Donald Trump are reportedly questioning the decision to launch the war against Iran, amid concerns within the administration that Tehran’s ability to withstand the conflict may have been underestimated, a report said.

According to the report by Axios, some key officials were reluctant or wanted more time before launching the campaign. One source said Trump ultimately brushed aside the hesitation, saying "I just want to do it.”

The source added that Trump had been encouraged by recent military successes, including last summer’s strikes on Iran and the January capture of Venezuelan President Nicolas Maduro, and had overestimated his ability to topple the Iranian regime without ground troops.

"He was high on his own supply,” the source told Axios.

The report noted that Trump has currently fallen into an "escalation trap” in the Strait of Hormuz, in which the stronger side feels compelled to continue attacking in order to demonstrate its superiority, even if gains are diminishing.

A senior administration official told Axios that Iranian interference with the strait was making Trump "more dug in” rather than prompting a reassessment.

On the timeline, the administration had initially anticipated a four- to six-week operation.

However, officials in Washington and allied capitals are now preparing for a longer crisis, with three sources telling the outlet that U.S. involvement could continue until September, even if the conflict shifted to a lower intensity phase.

The US-Israeli strikes on Iran began Feb. 28 and have reportedly killed around 1,300 people, including then-Supreme Leader Ali Khamenei, according to officials and external reporting. Fourteen U.S. service members have been killed since the beginning of the campaign.