WASHINGTON — One of the American Navy’s oldest transport ships, now converted into a “floating base” has arrived off the coast of Bahrain to support counter-mine operations in the Persian Gulf as U.S. steps up military pressure on Iran, The New York Times reported Thursday.

The deployment of the USS Ponce marks the latest in a gradual build-up of American forces in the region since tensions spiked with Iran in December over its nuclear programme, with Tehran threatening to possibly close the strategic Strait of Hormuz.

Equipped with a helicopter landing deck and space for troops, the amphibious ship, in service since 1971, can support an array of missions as a “forward staging base” involving special forces, countermine operations or repair work for warships, officials said.

The keel for the ship, the Ponce, was cast in 1966, and the vessel, nearing the end of its service, was to have been scrapped, the newspaper said. But the Ponce was reborn as a floating forward base for staging important military operations across the region — the latest example of the new American way of war.

The mission of the reborn Ponce was designed to counter the threats from Tehran to close the vital commercial waterway. Tehran made the threat when US and Israel spoke about launching air attacks on Iran's nuclear facilities.

In its role, the Ponce will be a launching pad for helicopters, a home to underwater diver teams and a seaborne service station providing fuel and maintenance for minesweeping ships, the Times said. But with the relatively simple addition of a modular barracks on the deck, the Ponce can also be a mobile base for several hundred Special Operations forces to carry out missions like hostage rescue, counterterrorism, reconnaissance, sabotage and direct strikes. Even with the addition of the barracks, there is ample room for helicopters and the small, fast boats favoured by commandos.

The Ponce operates from international waters. "Surprise and speed are critical to military success; the Ponce can sail close to areas of conflict. And having the ability to carry out different missions for different branches of the armed services is more valuable than having a weapons platform that does just one thing for one branch of the military," the Times said.