According to DoD spokeswoman Lieutenant Colonel Michelle Baldanza, a US reconnaissance aircraft was flying in a "routine patrol" in international airspace on May 17 when "two tactical aircraft from the People's Republic of China" intercepted the plane.
In traditional rhetoric, the DoD labeled the intercept "unsafe and unprofessional," a commonplace code-phrase used when a US military plane or ship encounters a foreign military plane at a distance of less than 50 feet.
Spokeswoman Baldanza noted in a written statement that, "Over the past year, DoD has seen improvements in PRC actions, flying in a safe and professional manner."
The incident is currently under investigation by US Pacific Command.
The incident took place over the South China Sea, a hotly-contested region through which roughly $5 trillion in trade passes annually by ship. It is almost entirely claimed by China, although portions of the sea are claimed by other countries, including the Philippines, Indonesia, Malaysia, Brunei, and Vietnam.
China has repeatedly claimed that the US is "militarizing" the South China Sea. Determined to enforce the "freedom of navigation" principle of international maritime law, the US military, along with allied forces from Australia and other countries, have established military naval and air patrols in the region.