An armed Chinese government ship was one of three vessels that entered Japan’s territorial waters near the disputed Diaoyu Islands Saturday, a Japanese Coast Guard official said. This is the first time that an armed vessel has come into the area Japan’s claims as its territory, the official said. The vessels approached waters north of Kuba Island from around 8.19 am local time, entering Japanese territorial waters starting from 9.30 am and left by 10.50 am, according to e-mailed coast guard statements. READ MORE: Japan spots cannon-like equipment on Chinese ship near disputed isles The armed vessel was the same one that the coast guard reported on December 22 was sailing in waters 28 km east-north-east of one of the islands, according to the official, who declined to be named, citing government policy. Kuba Island is among East China Sea islands whose sovereignty is disputed by Japan and China. Ships from both nations have been tailing one another in the area since Japan bought three of the uninhabited islands from a private owner in 2012. The dispute is among the biggest diplomatic issues between the two nations. When Japan’s coast guard warned the Chinese to leave its territorial waters Saturday, they responded by saying that the Japanese vessel was in Chinese waters and should leave immediately, Kyodo reported. One of the vessels was armed with an auto-cannon, Kyodo said. This is the 35th time this year that vessels of the Chinese government have entered Japan’s territorial waters, according to Kyodo. READ MORE: Japan defence budget set to top 5 trillion yen, including funds to bolster disputed islands Japan’s cabinet approved a record defence budget December 24 amid China’s increasing military activity in the region. The US$42 billion package is an increase of 1.5 per cent from the current fiscal year ending March, marking the fourth straight annual gain under the administration of Prime Minister Shinzo Abe. It accounts for just over 5 per cent of the overall 96.7 trillion yen budget for next fiscal year, also approved December 24. While Abe has denied Japan will send maritime forces to back up US navigation exercises in the South China Sea, he’s said he supports the freedom of navigation operations that are challenging China’s claims to one of the world’s busiest waterways.