Japan is sending its largest warship to protect a US vessel as it resupplies the strike group led by carrier Carl Vinson amid tensions with North Korea.

The 800ft helicopter carrier Izumo left its home port of Yokosuka, south of Tokyo, on Monday to escort the American vessel to the waters off Shikoku, around 400 miles away at the top end of Japan's south island.

The supply vessel, which is not being named, is believed to be in the region to support the 'armada' sent by President Trump to warn Kim Jong-un off conducting a sixth nuclear test.

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Japan has deployed the Izumo (top), its largest ship built since the Second World War, to escort a US supply vessel (bottom) which is believed to be supporting the carrier USS Carl Vinson

The last time the Japanese and American navies were on active deployment in the Pacific together, they were fighting. On Monday carrier Izumo (bottom) guarded a US vessel (top)

The 800ft Izumo, a helicopter carrier, left its port near Tokyo on Monday and is thought to be making a 400 mile trip to the waters near Shikoku alongside the US vessel

The Izumo appears similar to American carriers, but is only designed to use helicopters as it lacks the launch mechanisms to get aircraft into the sky

The Izumo is Japan's largest vessel constructed since the Second World War, and its active deployment marks the first time new powers expanding the role of the country's military have been used.

Japan's pacifist constitution, which was adopted after its surrender to America in 1945, forbid its military from carrying out any action that was not in self-defense.

However, Prime Minister Shinzo Abe expanded the definition of self-defense last year to include protecting Japanese allies and providing logistical support to countries who are important to the defense of the country.

The Izumo's deployment marks the first time Japan has used new powers which allow its military to carry out actions that are not purely in self-defense

Japan's pacifist constitution, signed after surrender to the US in 1945, was changed in December last year to allow the country to defend allies (pictured, the Izumo on Monday)

The Izumo (pictured leaving port) has been authorized to use 'minimal firepower' in order to protect the supply vessel, according to local reports

The powers also allow the military to shoot down a North Korean nuclear missile, and may allow minesweeping to take place to clear lanes for Japanese supply ships.

The Izumo has been authorized to use 'minimal firepower' in order to protect the supply vessel, it has been reported.

North Korea has continued testing long-range missiles despite the Vinson's presence, with the latest coming on Saturday, though a much-anticipated sixth nuclear test has not yet taken place.

On Monday, the country's communist regime warned that it would carry out the test 'at any time and at any location' set by its leadership.

The USS Carl Vinson (pictured) is currently in the waters of the Korean Peninsula as Donald Trump and Kim Jong-un face off over a sixth nuclear test by North Korea

Jong-un has repeatedly said he will carry out a fresh nuclear test 'at any time' and warned his military is capable of sinking the Vinson with a 'single strike'

A spokesman for the North's foreign ministry said Pyongyang was 'fully ready to respond to any option taken by the US'.

The regime will continue bolstering its 'preemptive nuclear attack' capabilities unless Washington scrapped its hostile policies, he told the state-run KCNA news agency.

Jong-un has said his regime is capable of sinking the Nimitz-class Vinson and an accompanying submarine, the USS Ohio, with 'a single strike'.

The USS Nimitz and USS Ronald Reagan and their accompanying strike groups are also being sent to the region after Trump promised to 'resolve' the North Korea issue.