By Yewon Kang and Sam Kim

Seoul: South Korea will extend its air-defence identification zone to cover islands and an underwater rock, adding to regional tensions that have escalated since China last month declared control over airspace claimed by neighbours.

The nation’s ADIZ will cover the islands of Marado and Hongdo and the underwater Ieodo seamount from 15 December, Kim Min Seok, a ministry of defence spokesman, said in a televised briefing in Seoul on Sunday. China rejected a demand made on 28 November to exclude from its zone Socotra Rock, where South Korea operates a research station and heliport. The submerged rock, called Ieodo in Korean and Suyan in Chinese, also falls under Japan’s air-defence zone.

“South Korea’s announcement was not surprising, it was a tit-for-tat action for the earlier Chinese move," Robert Kelly, an associate professor in the department of political science and diplomacy at Pusan National University, said by phone on Sunday. Tensions will rise and continue for years, now with three nations’ overlapping zones.

The Chinese ADIZ covers a swathe of the East China Sea, including islands at the centre of a territorial dispute with Japan. The US, South Korea and Japan have all run unannounced military flights through the area in a test of Chinese resolve.

China has more than doubled defence spending since 2006 and continues modernizing its forces, even as the US dedicates more military resources to the Asia-Pacific and Japan expands its own navy. The relative gap indicates China—which also is advancing naval deployments in waters it claims in the South China Sea—may be constrained to challenge incursions over East China Sea airspace.

Biden comments

US vice-president Joe Biden said on 6 December in Seoul that he had told Chinese leaders during his trip to Beijing that China’s declaration wouldn’t affect US military operations in the region even as it increased the risk of miscalculations.

He spoke after receiving a briefing from President Park Geun Hye on South Korean’s position regarding China’s ADIZ when the two met in Seoul hours earlier, according to her presidential office.

“We appreciate the ROK’s efforts to pursue this action in a responsible, deliberate fashion by prior consultations with the United States and its neighbours, including Japan and China," state department spokeswoman Jen Psaki said on Sunday in an email, referring to South Korea’s official name, the Republic of Korea.

Biden’s trip to Japan, China and South Korea was originally intended to focus on the 12-nation Trans-Pacific Partnership trade pact and reinforce a renewed US emphasis on the region. That agenda was overtaken by China’s 23 November ADIZ declaration.

As China gathers strength in the Asia-Pacific it will have to compete with a much larger US military—whose air force alone has more than 400 surveillance planes compared with 100 in all China’s armed forces, for example—as the Obama administration conducts what it calls a rebalance to the region. Bloomberg