President Donald Trump's administration is considering deploying thousands of US troops to reinforce its operation in the Middle East, as the US military prepares for possible next steps in its campaign against Iran, said a US official and three people familiar with the matter, Reuters reports.

The deployments could help provide Trump with additional options as he weighs expanding US operations, with the Iran war well into its third week.

Those options include securing safe passage for oil tankers through the Strait of Hormuz, a mission that would be accomplished primarily through air and naval forces, the sources said. But securing the Strait could also mean deploying US troops to Iran's shoreline, said four sources, including two US officials.

The Trump administration has also discussed options to send ground forces to Iran's Kharg Island, the hub for 90% of Iran's oil exports, the three people familiar with the matter and three US officials said. One of the officials said such an operation would be very risky. Iran has the ability to reach the island with missiles and drones.

Trump administration officials have also discussed the possibility of deploying US forces to secure Iran's stocks of highly enriched uranium, one of the people familiar with the matter said.

The sources did not believe a deployment of ground forces anywhere in Iran was imminent but declined to discuss specifics of US operational planning. Experts say the task of securing Iran's uranium stockpiles would be highly complex and risky, even for US special operations forces.

A White House official, speaking on condition of anonymity, said: "There has been no decision to send ground troops at this time, but President Trump wisely keeps all options at his disposal. The president is focused on achieving all of the defined objectives of Operation Epic Fury: destroy Iran's ballistic missile capacity, annihilate their navy, ensure their terrorist proxies cannot destabilize the region, and guarantee that Iran can never possess a nuclear weapon."