Pentagon Expects China to Export Stealthy Fighter

China is expected to export a new radar-evading fighter jet as well as other advanced weapons systems in a move that could potentially see them deployed against the U.S. or its allies, a senior Pentagon official said Tuesday.

Frank Kendall, the Pentagon's procurement chief, also told a congressional hearing that the technology gap between U.S. and Chinese weapons was set to continue narrowing as the countries' military spending moved in opposite directions.

"In general, we would expect the Chinese to have export versions of the equipment that they build," said Mr. Kendall told the House Armed Services Committee.

"One of the concerns about China is not just that they are modernizing—we don't anticipate a conflict with China, certainly—but they do export," he said. "And the weapons systems they develop we would face potentially with other people."

China is already the world's fifth-largest arms exporter, according to the Stockholm International Peace Research Institute, a think tank, and its state-controlled weapons makers have in recent years gained more success in high-profile international sales contests.

The expansion has posed a challenge for policy makers and western arms makers, who are targeting more sales in the Middle East and Asia to counter flat or declining defense budgets in the U.S. and Europe.

The industry was rocked last year when Turkey indicated it would buy a missile-defense system from China, beating rival bids from Raytheon Co and consortia from Europe and Russia.

Turkey has yet to finalize a contract, but Western diplomats questioned how a missile-defense system built with Chinese hardware could work alongside the existing technology provided by the country's allies in the North Atlantic Treaty Organization.

While the Pentagon has for several years expressed concern that the U.S. was losing its superiority in areas such as fighter jets, missile-defense systems and cyberwarfare, it is the first time that a senior official has raised the potential for China's new Chengdu J-20 fighter to be exported.

The J-20 first flew in 2011, and while Pentagon officials don't expect it to enter active service before 2018, its arrival could come at a time when governments could face a shrinking array of western-built jets to buy.

Heavy investment in the Lockheed Martin Corp F-35 fighter by the U.S. and some allies has raised questions over the ability of Boeing Co to continue building its F-15 and F-A/18 aircraft as its order book runs down. Similarly, rival aircraft built by the Eurofighter consortium and France's Dassault Aviation SA are suffering from a dearth of new orders, and fiercely contesting the few international contracts now on offer.

Mr. Kendall, Under Secretary of Defense for Acquisition, Technology and Logistics, has championed continued investment in research and development by the Pentagon to keep pace with higher spending by China, Russia and others.

"The Department of Defense is being challenged in ways that I've not seen in decades," said Mr. Kendall,, at a congressional hearing on the "pivot" of U.S. military forces back to Asia from the Middle East.

Mr. Kendall said while China's published defense budget remained just a quarter of that in the U.S., it was growing at around 10% a year and allowed for more equipment buying because of its comparatively lower personnel costs.

The official said that while he was "comfortable now" with the military balance between the nations in the Pacific, U.S. funding challenges clouded the medium-term outlook. "I'm not sure we'd be able to say that five or 10 years down the road," said Mr. Kendall.

He pointed to recent reports of a test by China of a hypersonic missile that is able to fly more than five times the speed of sound, making it difficult to track and destroy.

"This is a good example of an area of technology that is going to move forward whether we invest in it or not," said Mr. Kendall.

The Wall Street Journal