US officials also announced new counter-drone capabilities and financial rewards for information on senior Iranian officials as war tactics. 

In the latest move, the US has offered rewards of up to $10 million for information on several senior Iranian figures, accusing them of directing operations through the Islamic Revolutionary Guard Corps (IRGC), which Washington designates as a terrorist organisation.

Through its Rewards for Justice programme, the US said individuals providing relevant information could also be eligible for relocation. Among those named are Mojtaba Khamenei, the son of Iran’s Supreme Leader, intelligence minister Esmail Khatib, senior adviser Ali Asghar Hejazi, military commander Yahya Rahim Safavi, Brigadier General Eskandar Momeni, and political figure Ali Larijani, secretary of Iran’s Supreme National Security Council.

The announcement came as Larijani appeared at pro-Palestinian al-Quds Day demonstrations in Tehran, posting images of his participation on social media.

At the same time, the United States is preparing to deploy a Marine expeditionary unit to the Middle East as hostilities continue to escalate.

According to US officials cited by ABC News, about 2,200 Marines are expected to deploy aboard three naval vessels. A defence official told Al Jazeera that the unit will depart from a United States Marine Corps base in Okinawa, Japan, and could include as many as 2,500 personnel travelling with accompanying naval assets.

Officials say the force is designed to support ongoing operations and could be used for emergency evacuations or amphibious landing missions if required.

Drone defences strengthened

Washington has also rushed thousands of interceptor drones to the region to counter Iranian aerial attacks.

Dan Driscoll, secretary of the United States Army, said that 10,000 interceptor drones were sent to the Middle East within five days of the start of the conflict between Israel and Iran on February 28.

The drones, known as Merops interceptors, are intended to provide a lower-cost alternative to traditional missile defence systems used to shoot down incoming threats.

Each interceptor costs between $14,000 and $15,000, according to US officials. Analysts say this still makes them more expensive than Iran’s widely used Shahed-136 drone, which some estimates place at about $7,000 per unit.

The latest US actions underline the expanding scope of the conflict, as Washington increases its military presence and intelligence efforts in response to Iranian capabilities.

With both sides continuing to deploy new resources and personnel to the region, analysts warn the confrontation between Israel, the United States and Iran could deepen further in the coming weeks, raising concerns about a broader regional war.