Carrying 3,500 Marines and F-35 stealth fighters, the USS Tripoli has arrived in the Middle East, raising speculation of a US ground assault on Iran's Kharg Island oil terminal.

The amphibious assault ship USS Tripoli has officially arrived in the Middle East. It brings an expeditionary force of 3,500 Marines and sailors directly into the active conflict zone.

This deployment pushes the total number of American troops in the Gulf region to over 57,000. Military analysts note this is the largest US military buildup in the Middle East since 2003.

Operating as a mobile military base, the USS Tripoli is heavily equipped. It carries F-35B stealth fighters, MV-22 Ospreys, and attack helicopters designed for rapid troop deployment.

Experts believe these Marines are positioned to potentially assault Kharg Island. This highly strategic Iranian island processes roughly 90 per cent of the country's crude oil exports.

A secondary objective for a ground invasion involves the Strait of Hormuz. Deploying forces along Iran's southern coastline could permanently break its military blockade on the vital waterway.

US Secretary of State Marco Rubio downplayed the immediate need for a full invasion. However, he confirmed these troop movements give the president "maximum optionality" for future contingencies.

The Pentagon is already preparing to send the USS Boxer with an additional 2,500 Marines. This ensures overwhelming ground power if the air campaign transitions to a physical occupation.