China should clarify its foreign ministry’s explanation on the Hainan rule that is allegedly limited to within 12 nautical miles of the province’s coast in the West Philippine Sea (South China Sea), the Department of Foreign Affairs said on Friday.

“We have asked China for further clarification on the statement of the Foreign Ministry spokesperson that the scope of Hainan’s rules is limited to within 12 nautical miles of Hainan’s coast,” Foreign Affairs spokesman Raul Hernandez said in a text message.

In December last year, Chinese Foreign Ministry spokesman Hua Chunying said that the new rules implemented by the Hainan province would be limited to waters extending only up to 12 nautical miles from its coast.

The supposed new rules, which took effect on January 1, this year authorize Hainan police to board and seize foreign vessels that pass by its coast.

“Was [the Chinese foreign ministry] referring to the coast of Hainan Island or some other coasts over which Hainan province considers it has jurisdiction?” Hernandez asked.

Hainan is the Chinese province that is now exercising jurisdiction over the contested islands in the West Philippine Sea.

Because most of the West Philippine Sea is being claimed by China, the departmetn fears of what China meant by saying that the rule will apply only to within 12 nautical miles of Hainan’s coast.

International maritime laws provide each country with jurisdiction up to 12 nautical miles from its coast. But if Hainan considers some islands in the West Philippine Sea under its jurisdiction, this will effectively extend the coastline.

The region, which fast became a potential military flashpoint, is in the middle of an embittering territorial conflict between China, the Philippines, Taiwan, Vietnam, Malaysia and Brunei Darussalam.

Tensions between Manila and Beijing heightened in April last year when the intervention of Chinese maritime surveillance ships in the seizing of Chinese fishermen by Philippine authorities resulted in a months-long standoff in Panatag (Bajo de Masinloc or Scarborough) Shoal.

The shoal which is called Huangyan Island by China, sits well within Manila’s 200-nautical mile exclusive economic zone as provided for by the United Nations Convention on the Law of the Sea.

The delineation of coastlines, exclusive economic zones and extended continental shelves has been subjected to much scrutiny and various interpretations because of the overlapping claims in the region.