Japan filed a protest with South Korea on Wednesday over a South Korean vessel's survey in a disputed exclusive economic zone (EEZ), Kyodo News said.

Japanese Vice Foreign Minister Shotaro Yachi summoned South Korean Ambassador to Japan Ra Jong Yil to file the protest in the morning, the report said.

According to the Japan Coast Guard, the South Korean ship was sailing in the disputed EEZ about 45 kilometers west-northwest of the islets known as Takeshima in Japan and Dokdo in South Korea around 6:40 a.m.

The survey in the disputed area is "quite regrettable and we demand an immediate halt" to it, Foreign Ministry Press Secretary Yoshinori Katori said in the statement in the morning.

Japan also may conduct its own maritime survey in waters near the islets, which had initially been planned in April, Katori said.

A Japan Coast Guard ship is following South Korea's survey ship, while a South Korean patrol ship is escorting the survey ship, Kyodo News said, quoting the Japan Coast Guard.

Seoul has confirmed that a 2,533-ton South Korean vessel launched a 12-day maritime research on Monday to collect data on salinity and temperature in a square section of waters between South Korea and Japan, including the waters near the disputed islets.

In April, Tokyo and Seoul closely averted a confrontation over the disputed islands when Japan announced the intention to survey the ocean bed around them, leading South Korea to threaten to block its neighbor by force.

The two countries compromised eventually, with Seoul dropping a proposal to submit Korean names for the area to an international oceanographic meeting and Japan calling off the maritime survey.

Source: Xinhua