CENTCOM said Monday's mission will use guided-missile destroyers, more than 100 aircraft and 15,000 troops, while a US official said it is not an escort operation.
Trump called Project Freedom a humanitarian step to help vessels trapped in the effectively closed waterway, where about 20,000 seafarers remain stranded and interference would be met forcefully.
The closure has pushed average US gasoline prices to $4.45 a gallon, while Washington and Tehran say peace discussions continue as Iran reviews the latest US response.
How will Iran respond to a U.S. operation that directly challenges its control over the Strait of Hormuz?
With global markets in turmoil, can a military escort operation truly reopen the world's most critical oil chokepoint?
Amid fragile peace talks, is 'Project Freedom' a genuine rescue mission or a prelude to a much wider conflict?