"The United States Central Command executed one of the most powerful bombing raids in the History of the Middle East, and totally obliterated every MILITARY target in Iran's crown jewel, Kharg Island," Trump said on social media.

"I have chosen NOT to wipe out the Oil Infrastructure on the Island. However, should Iran, or anyone else, do anything to interfere with the Free and Safe Passage of Ships through the Strait of Hormuz, I will immediately reconsider."

The United States and Israel have treaded carefully around the island, but Trump administration officials have been reported as saying that capturing Kharg was on the table as the war in the Middle East persists.

The island, located around 30 kilometers (19 miles) off the Iranian mainland, handles roughly 90 percent of Iran's crude exports, according to a recent JP Morgan note.

Any move on the territory, which is about one-third the size of Manhattan, would have swift repercussions, experts said.

"A direct strike would immediately halt the bulk of Iran's crude exports, likely triggering severe retaliation in the Strait of Hormuz or against regional energy infrastructure," JP Morgan said.

Iranian strikes have all but halted maritime traffic in the Strait of Hormuz -- through which a fifth of global crude oil and liquefied natural gas normally pass -- and have also impacted oil infrastructure in other Gulf states.

Trump on Friday said the US Navy would start escorting tankers through the straits "very soon" to restore oil exports as he struggles to tackle soaring US gas prices.

Kharg underwent key developments during Iran's oil expansion in the 1960s and 1970s, with much of the country's coast too shallow for supertankers.