The U.S. Navy hopes to expedite the return to the Persian Gulf of two ships refitted for minesweeping now undergoing maintenance in Singapore, a senior U.S. official said on Wednesday, as concerns mount over Iranian threats to mine the Strait of Hormuz.

The official acknowledged the United States had "not a lot of options" in the Indian Ocean to maintain the two littoral combat ships based out of Bahrain, saying it hoped to minimize time spent laid up in Singapore, 3,915 miles away.

The work would be completed as soon as possible to prepare the ships to get "back into the theater" where they were based, the official said, declining to provide a time frame and speaking on the condition of anonymity.

Since the start of the U.S.-Israeli war on Iran, Tehran has attacked countries that host U.S. bases and effectively closed the Strait of Hormuz, a conduit for a fifth of the world's oil and liquefied natural gas, causing the worst energy supply shock in history.

Iran has deployed mines in the Strait, sources have said, and its Defense Council on Monday warned various types of mines, including floating mines deployed from the coast, could be used if the U.S. were to blockade Kharg Island, Tehran's main oil export hub.

The official said the ships had been at sea for quite some time due to military operations and needed to be refitted and undergo maintenance.

The U.S. Navy has decommissioned Bahrain-based Avenger-class ships designed as minesweepers, replacing them with littoral combat ships that can be fitted out with mine-countermeasure equipment. Asked what minesweeping capacity the United States currently has in the Middle East while the ships were in Singapore, the official said the military's mine warfare capabilities included unmanned undersea vehicles, four Avenger-class vessels, helicopters, and divers.