SEOUL : South Korea declared Sunday an expanded air defence zone that overlaps with one recently announced by China and covers a submerged rock disputed by the two countries as regional tensions soar over competing territorial claims. Seoul's defence ministry said its new zone, which will take effect on December 15, would cover Ieodo - a submerged rock in waters off its south coast, which China calls Suyan. The airspace above the Seoul-controlled rock - long a source of tension between South Korea and China - is also covered by Beijing's zone. China last month unilaterally declared an Air Defence Identification Zone in the East China Sea, asking foreign planes to identify themselves. But the zone - which encompasses some areas currently controlled by South Korea or Japan - has drawn intense protests from the two neighbours and objections by their key allies and the United States.

"We will coordinate with related countries to fend off accidental military confrontations and to ensure safety of airplanes," defence ministry spokesman Kim Min-Seok said.

Seoul had notified its neighbours in advance about its new air zone - the first revision in its air defence area in 62 years, he added.

The zone was expanded about 66,480 square kilometres (25,670 square miles) - or about two thirds of the size of the country - in waters off its south coast, a defence ministry spokesman told AFP.

Tension has been high since China declared its new air defence zone, which its neighbours fear is part of a push to assert its growing military might and back up its claims in territorial disputes.

The ADIZ also covers areas over the Tokyo-controlled islands known as Senkaku in Japan and Diaoyu in China that have been at the centre of a simmering territorial row.

Tokyo and Seoul have rejected Beijing's demand that all aircraft traversing the zone file flight plans and ID details.

The US flew two US B-52 bombers through the area without complying, followed by similar moves by Japan and South Korea whose planes also entered the zone without notifying China.