Three Chinese coast guard vessels entered Japan's territorial waters near the Senkaku Islands on Wednesday, a day before the 50th anniversary of the normalization of the countries' diplomatic ties.
The Japan Coast Guard said the intrusion, the 27th this year and the first since Sept. 8, off the uninhabited islets claimed by China occurred around 3:15 a.m. after the ships tracked three Japanese fishing boats.
Japanese patrol vessels ordered the Chinese ships to immediately exit the waters near the Senkakus, a longtime source of tension between the countries, with neither side in the mood for a grand celebration on the key political anniversary.