Donald Trump has threatened to destroy Iran's electricity generating plants, oil wells, Kharg Island and potentially all desalination plants if negotiations with what he described as a "new and more reasonable regime" fail to produce a deal and the Strait of Hormuz is not opened.

The US president posted the warning on Truth Social on March 30, saying serious discussions were under way with new Iranian leadership but that military operations would conclude with the destruction of infrastructure targets if talks collapsed.

"If for any reason a deal is not shortly reached, which it probably will be, and if the Hormuz Strait is not immediately open for business, we will conclude our lovely stay in Iran by blowing up and completely obliterating all of their electric generating plants, oil wells and Kharg Island, and possibly all desalination plants, which we have purposefully not yet touched," Trump wrote.

He framed the threatened strikes as retribution for US military casualties during the war, citing what he called 47 years of the Iranian regime's "reign of terror."

The post is the most explicit threat yet to target Iran's civilian energy and water infrastructure, and comes despite Iran's parliament speaker Mohammad Bagher Ghalibaf previously warning that any attack on Iranian power plants would result in energy infrastructure across the entire region being treated as legitimate targets.

Trump's reference to a "new and more reasonable regime" appears to acknowledge the political transition in Tehran following the death of Supreme Leader Ali Khamenei on February 28, with Mojtaba Khamenei having been elected as the new supreme leader by the Assembly of Experts in early March.

Kharg Island handles the vast majority of Iran's crude oil exports and has continued operating throughout the war. Its destruction would effectively end Iran's oil revenue for years and represent one of the most significant single strikes on a country's economic infrastructure in modern warfare.

Joe Kent, former US counterterrorism director, called on the public to contact the White House and members of Congress to prevent the deployment of ground forces to the region following the start of clashes with Iran.