WASHINGTON (Kyodo) -- China's military has expanded overwater bomber operations farther from the country's shores, likely training for strikes against the United States and its allies, including Japan, the U.S. Defense Department said Thursday.
In an annual report to Congress on military and security developments involving China, the Pentagon referred to an August 2017 flight by six People's Liberation Army Air Force H-6K bombers through the Miyako Strait, south of Okinawa's main island, which for the first time turned north to fly east of Okinawa and as far north as the Kii Peninsula in western Japan.
"These flights demonstrated a maturing capability for H-6K bombers to conduct off-axis strikes against U.S. and allies facilities," the report said.
"Previously demonstrated flight endurance of the PLAAF H-6K suggest future missions could fly around Japan, along the Philippines' coast, and use a wider area of operations throughout the Philippine Sea than current operations by Chinese aircraft," it said.
The H-6K's capabilities provided the PLAAF with an offensive strike capability against Guam with land-attack cruise missiles, the report added.
Last year, PLA bombers flew a dozen operational flights through such routes as the Sea of Japan, into the Western Pacific, around Taiwan, and over the East and South China Sea, according to the paper.
The department warned the PLA may continue to extend its operations beyond the so-called first island chain, which stretches from the Japanese archipelago through Taiwan to the Philippines, in a show of "the capability to strike U.S. and allies forces and military bases in the western Pacific Ocean, including Guam."
The Pentagon suspects Beijing may use such flights as "a strategic signal to regional states, although the PLA has thus far not been clear what messages such flights communicate beyond a demonstration of improved capabilities."
The report also said the PLA Air Force has been reassigned a nuclear mission, and that the deployment of nuclear-capable bombers would, for the first time, provide China with a nuclear "triad" of delivery systems dispersed across land, sea and air.
According to the Pentagon, China in 2017 maintained a presence in the Senkaku Islands "usually with four China Coast Guard ships" and entered within 12 nautical miles of the East China Sea islets "an average of once every 10 days with multiple CCG ships" in an attempt to undermine the Japanese administration of islands.
"China continues to use maritime law enforcement ships and aircraft to patrol near the islands," the report said. "The United States opposes any unilateral actions that seek to undermine Japan's administration of the islands."
In the South China Sea, no substantial Chinese land reclamation occurred in 2017, but Beijing continued building infrastructure at three large Spratly Islands outposts in an attempt to assert its claims in disputed waters.
"China continued outreach to South China Sea claimants to further its goal of effectively controlling disputed areas," the report said.
Beijing has overlapping territorial claims with Brunei, Malaysia, the Philippines, Vietnam and Taiwan in the South China Sea, a strategic waterway through which over one-third of global trade passes.
The report said that should a crisis or conflict occur on the Korean Peninsula, the PLA could step into North Korea to defend its neighbor but that "China's willingness to intervene into North Korea to defend Kim Jong Un is unclear."
It did not, however, elaborate on Washington's assessment of how Beijing would deal with the North's leader in the event of a contingency.
"China's objectives for the Korean Peninsula include stability, denuclearization, and no U.S. forces near China's border," it said. "China's priority is maintaining stability on the Korean Peninsula, which includes preventing a DPRK collapse and preventing a military conflict on the peninsula."
DPRK is the acronym of North Korea's official name, the Democratic People's Republic of Korea.