TOKYO (Reuters) - Japan will accelerate spending on advanced stealth fighters, long-range missiles and other equipment over the next five years to support U.S. forces facing China’s military in the Western Pacific, two new government defense papers said.

FILE PHOTO: A Marine Corps pilot prepares for a vertical landing of Lockheed Martin F-35B stealth fighter aboard the USS Wasp amphibious assault carrier during their operation in the waters off Japan's southernmost island of Okinawa March 23, 2018. REUTERS/Issei Kato/File Photo

The plans are the clearest indication yet of Japan’s ambition to become a regional power as a military build-up by China and a resurgent Russia puts pressure on its U.S. ally.

“The United States remains the world’s most powerful nation, but national rivalries are surfacing and we recognize the importance of the strategic competition with both China and Russia as they challenge the regional order,” said a 10-year defense program outline approved by Prime Minister Shinzo Abe’s government on Tuesday.

The United States, followed by China, North Korea and Russia, are the countries that most influenced Japan’s latest military thinking, the paper said.

China, the world’s second biggest economy, is deploying more ships and aircraft to patrol waters near Japan, while North Korea has yet to fulfill a pledge to dismantle its nuclear and missile programs.

In Beijing, Foreign Ministry spokeswoman Hua Chunying said Japan was “singing the same old tune” and making “thoughtless remarks” about China’s normal defense activities.

“What Japan is doing here is neither conducive to improving and developing China-Japan relations, nor to the broader picture of regional peace and stability,” Hua told a news briefing.

“China expresses strong dissatisfaction and opposition at this and has already lodged stern representations with Japan,” she added.

Russia, which continues to probe Japan’s air defenses, said on Monday it built new barracks for its troops on islands seized from Japan at the end of World War Two.

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MORE STEALTH FIGHTERS

Japan plans to buy 45 Lockheed Martin Corp LMT.N F-35 stealth fighters, worth about $4 billion, in addition to the 42 jets already on order, according to a separate five-year procurement plan approved on Tuesday.

The new planes will include 18 short take off and vertical landing (STOVL) B variants of the F-35 that planners want to deploy on Japanese islands along the edge of the East China Sea.

The islands are part of a chain stretching past Taiwan and down to the Philippines that has marked the limit of Chinese military dominance east of the disputed South China Sea.

“Japan’s decision to acquire more F-35s is a testament to the aircraft’s transformational capability and its increasing role in promoting regional stability and enhancing the US-Japan security alliance,” Lockheed Martin said in a statement.

The navy’s two large helicopter carriers, the Izumo and Kaga, will be modified for F-35B operations, the paper said.

The 248-metre (814 ft) long Izumo-class ships are as big as any of Japan’s aircraft carriers in World War Two. They will need reinforced decks to withstand the heat blast from F-35 engines and could be fitted with ramps to aid short take-offs, two defense ministry officials told Reuters.

TRADE WAR THREAT

The new F-35 order may also help Japan avert a trade war with the United States.

U.S. President Donald Trump, who has threatened to impose tariffs on Japanese car imports, thanked Abe for buying the F-35s when the two met at a summit in Argentina this month.

Other U.S.-made equipment on Japan's shopping list includes two land-based Aegis Ashore air defense radars to defend against North Korean missiles, four Boeing Co BA.N KC-46 Pegasus refueling planes to extend the range of Japanese aircraft, and nine Northrop Grumman NOC.N E-2 Hawkeye early-warning planes.

Japan plans to spend 25.5 trillion yen ($224.7 billion) on military equipment over the next five years, 6.4 percent higher than the previous five-year plan. Cost-cutting will free up another 2 trillion yen for purchases, the procurement paper said.

Japan only spends about 1 percent of its gross domestic product (GDP) on defense, but the size of its economy means it already has one of the world’s largest militaries.

"The budget is increasing and there has been an acceleration to deploy capability as soon as possible," Robert Morrissey, head of Raytheon Co's RTN.N unit in Japan, said this month.

Wary of North Korean promises to abandon ballistic missile development, Japan’s military is buying longer-range Raytheon SM-3 interceptor missiles able to strike enemy warheads in space.

The defense papers assessed non-traditional military threats as well. A new joint-forces cyber unit will bolster Japan’s defenses against cyber attacks.

More electronic warfare capabilities are planned, and the air force will get its first space unit to help keep tabs on potential adversaries high above the Earth’s atmosphere.