South Korea is set to submit a formal claim to an extended portion of its continental shelf to the United Nations, a government official said Sunday, amid spiraling territorial tension across the region.

The Foreign Ministry has been preparing official documents to present to the U.N. Commission on the Limits of the Continental Shelf for a scientific and technical review and recommendation.

“Having decided to turn them in within this year, we’ve already reported the plan to Cheong Wa Dae and will refer it to the Cabinet on Tuesday,” a senior ministry official told The Korea Herald, adding that no date has been fixed yet.

The ministry plans to argue that the country’s continental shelf “naturally” stretches to the Okinawa Trough in the East China Sea.

Seoul and Beijing share a largely similar stance and have been “exchanging views” to counter Tokyo’s maritime assertiveness, he added. The Japanese government rejected the two countries’ joint preliminary claim filed in 2009.

Though the agency’s advice has no legal binding force, “earning recognition from the international community could give power to our claim,” the official said on condition of anonymity due to the sensitivity of the matter.

The plan comes amid rows 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. The areas are believed to hold huge oil and gas deposits.

The outer limit of an exclusive economic zone typically does not exceed 200 nautical miles (370 kilometers) from the baselines. But the U.N. Convention of the Law of the Sea allows signatories to claim control of the underlying seabed beyond that limit by proving the ocean floor is connected to its continental shelf. If another country objects, it shelves the proposal until the stakeholders settle themselves.

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