A Russian SU-27 Flanker fighter jet intercepted a U.S. surveillance plane off Russia's east coast near Japan in April, flying unusually close, as tensions rose over the Ukraine crisis.
The U.S. RC-135U Combat Sent electronic intelligence plane was conducting a routine mission over the Sea of Okhotsk, north of Japan, on April 23 when the Russian fighter flew within about 30 meters (100 feet) of its nose, Rear Adm. John Kirby, a Pentagon spokesman, said Tuesday.
The incident coincided with President Barack Obama's arrival on a visit to Japan, during which he criticized Russia over its annexation of Crimea. Prime Minister Shinzo Abe's government has joined other Group of Seven nations in applying sanctions against Russia, disrupting Abe's effort to strengthen ties between the two countries and resolve a decades-old territorial dispute.
Asked why the Pentagon didn't disclose the incident until it was reported Tuesday by the Washington Free Beacon, Army spokesman Col. Steve Warren said, "I don't have a good answer for you."
Russia has stepped up military activity around Japan's borders in recent months. Japan dispatched jets to intercept Russian aircraft close to its airspace 359 times in the year to March 31, up from 248 times the previous year.