YOKOHAMA, Japan (AP) -- Japan on Tuesday unveiled its biggest warship since World War II, a huge flat-top destroyer that has raised eyebrows in China and elsewhere because it bears a strong resemblance to a conventional aircraft carrier.

The ship, which has a flight deck that is nearly 250 meters (820 feet) long, is designed to carry up to 14 helicopters. Japanese officials say it will be used in national defense — particularly in anti-submarine warfare and border-area surveillance missions — and to bolster the nation's ability to transport personnel and supplies in response to large-scale natural disasters, like the devastating earthquake and tsunami in 2011.

Though the ship — dubbed "Izumo" — has been in the works since 2009, its unveiling comes as Japan and China are locked in a dispute over several small islands located between southern Japan and Taiwan. For months, ships from both countries have been conducting patrols around the isles, called the Senkaku in Japan and the Diaoyutai in China.

The tensions over the islands, along with China's heavy spending on defense and military modernization, have heightened calls in Japan for beefed-up naval and air forces. China recently began operating an aircraft carrier that it refurbished after purchasing from Russia, and is reportedly moving forward with the construction of another that is domestically built.

Japan, China and Taiwan all claim the islands.

Though technically a destroyer, some experts believe the new Japanese ship could potentially be used in the future to launch fighter jets or other aircraft that have the ability to take off vertically. That would be a departure for Japan, which has one of the best equipped and best trained naval forces in the Pacific but which has not sought to build aircraft carriers of its own because of constitutional restrictions that limit its military forces to a defensive role.

Japan says it has no plans to use the ship in that manner.

The Izumo does not have catapults for launching fighters, nor does it have a "ski-jump" ramp on its flight deck for fixed-wing aircraft launches.