Japan's Defense Ministry says the Air Self-Defense Force carried out a joint training exercise with the US Air Force on Thursday over the East China Sea and the Sea of Japan.
According to the announcement made on Friday, 16 Japanese fighter planes, mostly F-15s, joined a US B-52 bomber in the drill.
Defense Minister Itsunori Onodera told reporters the exercise was aimed at boosting the deterrence and response capacity of the Japan-US alliance.
He added that strengthening Japan-US cooperation is an effective way to demonstrate Japan's resolve and high capabilities to stabilize the region at a time when the security environment is becoming increasingly severe.
Similar joint air drills over the East China Sea have been held before, but this is the first time the Defense Ministry has made an announcement about them.
Observers say the move is apparently aimed at China, which has increased its activities in the region.