Japan Maritime Self Defense Force's helicopter carrier Izumo at in Yokosuka Tokyo Dec. 6, 2016. It will join the United States in drills in the South China Sea in May. Reuters

Japan’s military was reportedly planning to take a firmer role in the ongoing South China Sea dispute by sending its biggest warship to the disputed waterway to train with the United States Navy in May, Reuters reported Monday citing three anonymous sources.

The report called the planned three-month-long training the “biggest show” of Japan’s navy since World War II as the Asian power intended to ship out its Izumo helicopter carrier to Singapore, Indonesia, the Philippines and Sri Lanka before meeting up with U.S. and Indian navy forces in the Indian Ocean in July. The vessel will then return to Japan in August.

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"The aim is to test the capability of the Izumo by sending it out on an extended mission," one source told Reuters. "It will train with the U.S. Navy in the South China Sea."

The U.S., Japan and South Korea have conducted many military exercises and drills in the region of late as well as in the past, but they have taken on new weight due to China’s actions in the South China Sea and North Korea’s latest missile tests.

Though Japan does have another maritime territorial dispute with China over the East China Sea, it went even further into the ever-evolving conflict over the hotly contested and valuable waterway by inviting Philippines President Rodrigo Duterte to visit the warship when it stops at Subic Bay just west of Manila, a source told Reuters.

The Philippines, along with Taiwan, Malaysia, Brunei and the U.S., have routinely challenged China’s massive claim to most of the South China Sea but Duterte had also attempted to improve relations with China and rebuffed the U.S.’ policies by visiting China in January and has planned another visit in May.

For more than the last two years, China has attempted to cement its perceived claim of the waterway by installing man-made, or artificial, islands and building military buildings and other installations despite a United Nations-backed court shooting down its claims last year.

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Following its loss in World War II, Japan was prohibited from growing its military unless it was for self-defense but it has continuously expanded its military budget for the last five years. In December, Japanese Prime Minister Shinzo Abe approved an increase of 1.4 percent to $43.6 billion, which included a $1.8 billion increase for the nation’s coast guard, BBC reported.