South Korea claimed an extended limit of its continental shelf in the East China Sea in a report to the United Nations on Wednesday, upping its ante in a heated race with Japan and China over fisheries and resources deposits.

The Foreign Ministry submitted to the U.N. Commission on the Limits of the Continental Shelf its claim to the edge of the country’s seabed beyond its 200 nautical mile (370 kilometer) exclusive economic zone from the baselines of its territorial waters.

The formal report maintains the outer limit of Korea’s continental shelf is closer to Japan, covering an area twice as large as in its 2009 preliminary statement, a senior ministry official said. The submission was based on research by the state-run Korea Institute of Geoscience and Mineral Resources.

The previous claim embraced 19,000 square kilometers in the Joint Development Zone with Japan, an 82,000-square-kilometer area south of Jeju Island.

The contest section is believed to hold rich fishing grounds and vast crude and natural gas reserves.

The U.N. CLCS is expected to review the document at a session in July. Its recommendation has no binding power and in case of an objection by another country, it shelves discussions until the stakeholders agree.

“The submission is does not mean that we have control over the claimed section of the continental shelf but to declare our geological recognition and the ground of the claim to the international community,” another ministry official told reporters on customary condition of anonymity.

On Dec. 14, China filed its own report to the agency, asserting that “geomorphologic and geological features” prove that its ocean floor stretches to the Okinawa Trough.

Beijing also slightly expanded its claim northeastward compared with its 2009 preliminary filing, widening the overlap with Korea’s.

The claims may trigger backlash from Japan, which rejected initial reports by Seoul and Beijing as a violation of its national interests. The two countries have been consulting with each other, apparently to counter Tokyo’s increasing maritime assertiveness.

Tension has been flaring between Japan and China over the islands of Senkaku or Diaoyu in the East China Sea. Tokyo also claims Korea’s islets of Dokdo in the East Sea.

By Shin Hyon-hee (heeshin@heraldcorp.com)