South Korea installs platform to monitor Chinese presence in disputed sea

SEOUL (Reuters) - South Korea has set up a "reciprocal" platform in a disputed area of the Yellow Sea, known in Seoul as the West Sea, where China has increasingly built structures, Oceans Minister Kang Do-hyung said on Wednesday.

China says its structures are fish farming equipment, but they have raised alarm bells in Seoul over concerns Beijing could be seeking to stake claims in the Provisional Maritime Zone, where the two countries' exclusive economic zones overlap.

Kang told parliament that South Korea is monitoring the Chinese presence by setting up a stationary floating platform for "environmental survey".

"South Korea has taken reciprocal measure with a large-scale floating object," he said.

In February, a South Korean research vessel sent to examine the Chinese structures was blocked by Chinese coast guard ships and rubber boats carrying civilians, according to South Korean media reports.

The South Korean coast guard also deployed and was involved in a two-hour stand-off before retreating, the reports said.

Lawmakers from South Korea's ruling People Power Party on Tuesday called the Chinese presence a "direct challenge to marine security" and urged a more forceful response.

Kwon Young-se, chairman of the party's emergency response committee, said China was using fishing as a pretext and compared its actions to those it has taken in the South China Sea, where Beijing claims vast swathes of the area, despite overlapping claims by Brunei, Indonesia, Malaysia, the Philippines and Vietnam.

"The West Sea is not just a sea, the West Sea is Korea," he said. "It is where many fishermen make their living, and the front line of our security."

In a statement on Wednesday, a spokesperson for the Chinese embassy in Seoul said some reports about the structures were not factual and that they do not violate any agreements.

"The fact is that the relevant facilities set up by China are deep-sea fishery aquaculture facilities located in China's coastal waters, which are China's reasonable use of offshore marine resources," the spokesperson said in a statement.

China maintains communication through diplomatic channels, and hopes to "avoid unwarranted politicization of the matter," the spokesperson added. "China and South Korea have maintained good and smooth communication on their differences related to the sea."

(Reporting by Josh Smith, Jack Kim, and Joyce Lee in Seoul, and Ryan Woo in Beijing; Editing by Saad Sayeed)