The document's security assessment on China comes after a section on Japan's ally, the United States, the first time Beijing has achieved second place in the Defence White Paper and pushing North Korea into the third position.

Russia, deemed by Japan as its primary threat during the Cold War, was in fourth place.

"It is a reflection of the fact that only the United States and China can project their influence globally," a Ministry of Defence official told a news briefing.

Japan has raised defense spending by a tenth over the past seven years to counter military advances by Beijing and Pyongyang, including defenses against North Korean missiles which may carry nuclear warheads, the paper said.

North Korea has conducted a series of short-range missile launches that Tokyo believes show Pyongyang is developing projectiles to evade its Aegis ballistic missile defenses.

To stay ahead of China's modernizing military, Japan is buying U.S.-made stealth fighters and other advanced weapons.

In its latest budget request, Japan's military asked for 115.6 billion yen ($1.1 billion) to buy nine Lockheed Martin F-35 stealth fighters, including six short take-off and vertical landing (STOVL) variants to operate from converted helicopter carriers.

The stealth jets, U.S.-made interceptor missiles, and other equipment are part of a proposed 1.2% rise in defense spending to a record 5.32 trillion yen in the year starting April 1.

By comparison, Chinese military spending is set to rise this year by 7.5% to about $177 billion from 2018, more than three times that of Japan. Beijing is developing weapons such as stealth fighters and aircraft carriers that are helping it expand the range and scope of military operations.

Once largely confined to operating close to the Chinese coast, Beijing now routinely sends its air and sea patrols near Japan's western Okinawa islands and into the Western Pacific.

China has frequently rebuffed concerns about its military spending and intentions, including a ramped-up presence in the disputed South China Sea, and says it only desires peaceful development.

The Defence White Paper said Chinese patrols in waters and skies near Japanese territory are "a national security concern".

The paper downgraded fellow U.S. ally, South Korea, which recently pulled out of an intelligence-sharing pact with Japan amid a spat over their shared wartime history. The move could weaken efforts to contain North Korean threats, analysts said.

Other partners, including Australia, the Association of Southeast Asian Nations (ASEAN) and India, feature more prominently in the defense paper.

"It's a reflection of the level of cooperation we undertake with each partner," the defense ministry official said.

REUTERS