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The Chinese air force has modified a small number of H-6 bombers apparently to carry a very large new anti-ship missile.

The new munition, possibly a variant of the DF-21D ballistic anti-ship missile, could pose a serious danger to U.S. Navy vessels operating in the western Pacific. Aircraft carriers, in particular, could be at risk.

The new H-6N variant of the venerable Chinese bomber -- itself a clone of the Soviet Tu-16 -- first appeared over Beijing during preparations for celebrations marking the 70th anniversary of the founding of the People’s Republic of China. Military parades and fly-overs are scheduled for Oct. 1, 2019.

The H-6Ns feature an under-fuselage recess that could accommodate a single, very large missile. The DF-21D is more than 30 feet long and weighs around 32,000 pounds. It can travel as far as 1,300 miles with a 1,200-pound warhead.

“Experts say that there at least four of these aircraft presently assigned to a People's Liberation Army Air Force bomber brigade in China's Central Theater Command region,” Joseph Trevithick wrote at The War Zone.

Reports about the H-6N and its ballistic-missile launching mission first began to emerge in 2017. Xi'an Aircraft International Corporation's H-6, a derivative of the Soviet-era Tu-16 Badger, has been the centerpiece of China's bomber force since the 1970s.

In 2009, the H-6K variant, a significant redesign from the original aircraft optimized as a carrier for long-range anti-ship and land-attack cruise missiles, entered service. The H-6N is a further outgrowth of this earlier missile carrier version.

The most notable change between the N and K is the complete elimination of the bomb bay on the N and the addition of semi-recessed area with a hard point for a large missile. This is similar in some general respects to the ability of Russia's Tu-22M Backfire bombers can carry a single Kh-22 or Kh-32 anti-ship cruise missile in a semi-recessed mount under its central fuselage.

There are no pictures from the parade preparations that show the H-6Ns carrying a payload and some of them appear to have a plug installed that gives the fuselage its normal profile when a missile is not loaded. So, it remains unclear what type of weapon, or weapons, the Chinese intend to employ on these aircraft.

But Trevithick thinks it’s the DF-21D. “Previous reports have indicated that an air-launched derivative of the DF-21D anti-ship ballistic missile, reportedly called the CH-AS-X-13, will be the primary weapon for the H-6N.”

Besides arming its bombers with a possible new missile, Beijing has been making efforts to diversify and harden its anti-ship arsenal.

The People's Liberation Army Rocket Force positioned at least a dozen transporter-erector-launcher vehicles for the DF-26 anti-ship ballistic missile at a previously undisclosed training range near Alxa in China's Inner Mongolia region, Jane's reported after reviewing DigitalGlobe satellite imagery dated Jan. 9, 2019.

The deployment reportedly was a response to the appearance of a U.S. Navy warship near the Paracel Islands on Jan. 7, 2019. The destroyer USS McCampbell sailed near the island group as part of a "freedom-of-navigation operation," or FONOP.

China, Vietnam and Taiwan all claim the Paracels, which lie around 650 miles from China's Hainan Island. In recent years China has dredged several reefs in the Paracels and built military outposts on them.

The U.S. Navy conducts FONOPs in order to assert its legal right to sail through international waters regardless of which country claims nearby territory. China's state-run Global Times new outlet described McCampbell's appearance near the Paracels as "trespass."

"McCampbell sailed within 12 nautical miles of the Paracel Islands to challenge excessive maritime claims and preserve access to the waterways as governed by international law,” Lt. Rachel McMarr, a U.S. Pacific Fleet spokesperson, told the news website of the U.S. Naval Institute.

The DF-26 is China's most powerful anti-ship missile. It's 46 feet tall and weighs 44,000 pounds. "The DF-26 comes with a 'modular design,' meaning that the launch vehicle can accommodate two types of nuclear warheads and several types of conventional warheads," the Center for Strategic and International Studies in Washington, D.C. reported.

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With a range of up to 2,500 miles and 4,000-pound payload, with satellite targeting the DF-26 in theory could strike U.S. Navy warships across the western Pacific Ocean. "Even when launched from deeper inland areas of China, the DF-26 has a range far-reaching enough to cover the South China Sea," an unnamed military expert told Global Times.

The DF-26, not to mention the DF-21D, could be vulnerable to the latest American defenses. The U.S. Navy's SM-6 interceptor missile theoretically is capable of hitting a DF-26 in two phases of its flight -- shortly after launch, as the Chinese missile is climbing and gaining speed, and then again in the DF-26's terminal phase, as it arcs down toward its target.

The missile, which arms U.S. Navy cruisers and destroyers, completed three successful test interceptions in 2015, 2016 and 2017, according to the U.S. Missile Defense Agency.

In moving a dozen DF-26 launchers to Inner Mongolia, around 2,000 miles from the Paracels, China reportedly aims to protect the rockets from boost-phase interception. "A mobile missile launch from deep in the country's interior is more difficult to intercept," Global Times paraphrased a Beijing-based military expert as saying.

The SM-6 can travel no farther than a few hundred miles. If China attacked an American warship from a missile base in Mongolia, the American ship's only chance of hitting the rocket would be during the final seconds of its flight.

An expert told Global Times a terminal interception is more difficult than a boost-phase interception would be. "After the missile enters a later stage, its speed is so high that chances for interception are significantly lower."

Even if the Americans can't shoot down the DF-26 or DF-21, it's unclear that the rockets reliably could hit a moving ship at sea from 2,000 miles or even just 1,000 miles away. "The accuracy of the DF-26 is uncertain," CSIS explained, "with speculators estimating the [circular error probability] at intermediate range between 150 to 450 meters," or around 500 to 1,500 feet.

David Axe serves as Defense Editor of the National Interest. He is the author of the graphic novels  War Fix, War Is Boring and Machete Squad.

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