Chinese maritime surveillance vessels were spotted Sunday traveling near the Senkakus, a group of islands at the heart of a bitter dispute between Tokyo and Beijing, for the first time since the Japanese government accused China of targeting weapons radar at a Japanese destroyer, the Japan Coast Guard said.

Four Chinese maritime surveillance vessels entered the so-called contiguous zone, adjacent to the territorial waters around the Japanese-controlled islet chain claimed by China, from around 7 a.m., according to the 11th Regional Coast Guard Headquarters in Naha, Okinawa Prefecture.

It is the first time since Tuesday that Chinese ships have been spotted near the Senkaku Islands in the East China Sea.

On Tuesday, the Defense Ministry said a Chinese frigate directed fire-control radar at a Maritime Self-Defense Force destroyer on the high seas in the East China Sea at around 10 a.m. on Jan. 30.

The ministry also said that another Chinese frigate was suspected of having directed fire-control radar at an MSDF helicopter in flight over the waters on Jan. 19.

Japan's accusations have been denied by China's Defense Ministry.

On Saturday, Japanese Defense Minister Itsunori Onodera said that the government of Prime Minster Shinzo Abe is considering disclosing evidence related to the radar incidents to prove that the accusations are correct.

The latest approach of Chinese surveillance ships came also after Onodera said their moves around the Senkaku Islands have "calmed" since the announcement on Tuesday.

Chinese maritime and fishery surveillance vessels have been sailing close to the Senkakus, sometimes entering Japanese territorial waters, since the dispute over the sovereignty of the uninhabited islands reignited after the Japanese government's purchase in September of a significant portion of them from a Japanese private owner.