A US Navy aircraft carrier and a guided-missile cruiser are heading to the waters near Yemen preparing to intercept weapons Iran is suspected of shipping to Shiite Houthi rebels there.
The USS Theodore Roosevelt and the USS Normandy will join some nine other American ships, including destroyers and cruisers, already in the area while eight Iranian vessels are steaming to the same site.
The US Navy has been beefing up its presence in the Gulf of Aden and the southern Arabian Sea amid intelligence about the Iranian convoy.
An anonymous Navy source told Associated Press that the US destroyers are prepared to confront arms-toting Iranian ships. But officials insisted on the record that the Roosevelt will be part of a deterrent, not an offensive, strategy. The Navy said the Roosevelt will simply "ensure the vital shipping lanes in the region remain open and safe." Pentagon spokesman Army Colonel Steve Warren denied that the ships are on a mission to intercept arms.
A UN Security Council passed a resolution last week that imposed an arms embargo on the Houthis.
The US ship movements come as Saudi Arabia and allies are turning up the action to vanquish the Houthi rebels, who seized the Yemen capital of Sanaa last year. The West insists Iran is supplying the rebels, a charge Iran denies.
The US and other Western allies are also providing intelligence and logistical support to the Sunnis launching airstrikes against the rebels. The latest attack, targeting a Sanaa scud missile base, killed dozens and wounded more than 300, Yemeni officials told Al Jazeera.