Two Chinese coast guard vessels repeatedly entered Japan's territorial waters near the Senkaku Islands on Sunday, the Japan Coast Guard said, intruding into the waters near the China-claimed islets the second day in a row.

The vessels first intruded into the waters near the group of uninhabited islets in the East China Sea at around 4:50 a.m., before leaving around 11:05 a.m. They then re-entered around 1:40 p.m. and left the area in the evening.

It was the ninth intrusion this year and the latest since a new law entered into force in China earlier this month, explicitly allowing its coast guard to use weapons against foreign ships that Beijing sees as illegally entering its waters. Japan has lodged protests over the repeated intrusions.

The Chinese vessels made a move to approach a Japanese fishing boat in the area carrying three passengers, the Japanese coast guard said.

A Japanese patrol vessel deployed around the fishing boat to ensure its safety warned the Chinese ships to leave Japanese territory, it said.

Two other Chinese vessels have also been spotted cruising in the so-called contiguous zone just outside Japan's territorial waters. One of them appears to be armed with an autocannon, the coast guard said.

Related coverage:

Quad members oppose attempts by China to alter regional status quo

2 more Chinese coast guard vessels enter Japan's waters near Senkakus

Japan ground troops to get transport vessels amid China's rise

A video supplied by Hitoshi Nakama, an assembly member from Ishigaki, Okinawa Prefecture, shows two Chinese coast guard vessels following a fishing boat he was on board as it operated near the Senkaku Islands from Feb. 15 to 16.

It also shows a Japan Coast Guard vessel sailing alongside to secure the boat's safety.

After returning to Ishigaki Port, Nakama described how the Chinese vessels stayed on the boat's tail for 27 hours and came as close as 40 to 50 meters away at times, saying it "was not a situation where you could fish safely."