The official said during an interview with Kyodo News it depends on U.S. allies to decide if the nuclear-armed Tomahawk cruise missiles will be decommissioned.

The remark apparently pays consideration to Japan, which has asked the United States not to unilaterally decide to reduce or abandon tactical nuclear arms.

Earlier this year, the Defense Department launched a review of its nuclear policy following President Barack Obama's call for a nuclear- free world.

The United States, which has promoted talks with Russia on a reduction of strategic nuclear arms, could maintain part of its tactical nuclear weapons arsenal out of political considerations over the U.S.-provided nuclear umbrella for its allies.

The official said the United States will consider the voices of its allies, while noting that a decision was postponed a few years earlier on whether to decommission or improve the "W80" nuclear devices on Tomahawk cruise missiles.

The official said one of the allies has appreciated Tomahawk cruise missiles as part of building up nuclear deterrence, while declining to identify the country.

Some U.S. military experts give low marks to nuclear-armed cruise missiles because bombers and submarines need to move closer to targets before firing. Those cruise missiles have a range of between several hundred kilometers and up to 3,000 km.

Former President George W. Bush's administration launched a review of deployment of nuclear-armed cruise missiles, including a possible phase out. But a final decision has been postponed.

Concerned about North Korea's nuclear development program and China's build-up of nuclear weapons, some Japanese government officials argue that the United States should maintain Tomahawk cruise missiles with nuclear devices.

Nuclear experts said the W80 device is a small thermonuclear warhead with an explosive yield of up to 150 kilotons TNT, more than 10 times as powerful than the atomic bomb dropped in Hiroshima in 1945. The United States began to produce the W80 in 1981. It will be gradually decommissioned in 2013 and beyond.

In an April speech in Prague, Obama laid out an ambitious vision for a world without nuclear weapons, saying the United States will take the lead in doing so as the only country that has used them.