The remarks at 9:00 pm (0100 GMT) will be Trump's first formal national speech on Iran from the White House since launching the war a month ago.

The White House has given few details on the address.

But Trump is expected to try and reassure the nation that US goals are being met and that he has a plan for completing the war, which has roiled the US economy and helped drive the 79-year-old Republican's polls into deeply negative territory.

Earlier Wednesday, Trump claimed a major breakthrough, saying Iran's president was seeking a ceasefire. This was swiftly denied by Iran's foreign ministry.

Trump has said he can see the war winding down within three weeks, repeatedly insisting that main objectives have been all but met.

Yet he has also threatened escalation, warning he could order targeting of Iran's civilian energy and drinking water infrastructure and even send in ground troops.

There has been especially mixed messaging from Trump on whether he will insist on Iran fully reopening the Hormuz Strait to oil and other commodity shipping or not.

As recently as Tuesday, Trump suggested this was not a key goal. However, on Wednesday he said he would consider a ceasefire only when Hormuz is "free and clear."

"Until then, we are blasting Iran into oblivion or, as they say, back to the Stone Ages!!!" he wrote on his Truth Social platform.

Recent polling shows Trump's overall approval rating slipping below 40 percent, with disapproval climbing above the mid-50s as voters sour on both the war and its economic fallout.

Support for the Iran campaign itself is underwater, with majorities opposing the offensive and independents turning sharply against it.

The economic picture has compounded the problem. Gasoline prices have surged above $4 a gallon (over $1 a liter) for the first time in years, while consumer confidence has weakened, dragging down Trump's already fragile standing on the economy.

- NATO rift -

Trump has rattled top US allies, calling for "reconsideration" of US membership in NATO after European countries declined to back the Iran campaign -- a stance that risks widening diplomatic damage already inflicted by Trump's trade wars and threats to take over Greenland.

Markets, however, seized on his more optimistic signals.

Global equities rallied and oil prices fell Wednesday on hopes of a near-term end to the conflict. Brent crude was down around one percent at $102.85 a barrel, while stock markets from Asia to Europe posted strong gains.

Still, analysts warned the underlying economic risks remain acute, with oil prices elevated and the Strait of Hormuz -- a conduit for roughly a fifth of global supply -- still effectively shut.

Beyond the markets, the strategic picture is increasingly difficult to reconcile with the administration's rhetoric, say its critics.

US and Israeli forces have struck thousands of targets and inflicted heavy damage on Iran's military infrastructure.

But the conflict has dragged on, the leadership in Tehran remains in place and the economic shock has spread globally -- raising questions about whether Trump can deliver a clear endgame.

That uncertainty has filtered into Washington, where even some of Trump's allies acknowledge the war has become a growing political liability ahead of November's midterm elections.

A White House official said the president's speech would highlight the success of the military campaign in achieving the goals sketched out "prior to the operation."

Although Trump's messaging has been inconsistent, the administration says these goals are to:

- destroy Iran's navy.

- destroy its missiles and production facilities.

- neutralize its militia proxies across the region.

- guarantee that Tehran can never obtain a nuclear weapon.

"He is expected to reiterate the two-to-three-week timetable for concluding the operation that he stated yesterday," the White House official said.