KUALA LUMPUR: Foreign Ministry called for a police investigation into a leaked diplomatic note from China over the South China Sea dispute.

The ministry said details of a February 18 diplomatic note from China’s Foreign Ministry to the Malaysian Embassy in Beijing was published by a Filipino media outlet on August 29. It didn’t give details but alluded to the South China Sea row in its statement.

The Philippine Daily Inquirer had published a diplomatic note in which Beijing reportedly demanded that Malaysia immediately halt all activities in an oil-rich maritime area off Sarawak.

The report said China had accused Malaysia of encroaching on areas covered by its 10-dash line, Beijing’s controversial map showing its claims to sovereignty in the South China Sea.

The diplomatic note also expressed Beijing’s displeasure over Malaysia’s oil and gas exploration activities near the Luconia Shoals near Sarawak, it said.

“The ministry views the leak of this document, which constitutes an official communication channel between the two countries, with grave concern,” Malaysian foreign ministry said in a statement.

Apart from calling for a police investigation, the ministry also said it will conduct an internal investigation into the breach of classified information.

Vietnam, Brunei, Malaysia, the Philippines and Taiwan all dispute Beijing’s claims to almost the entire South China Sea.

Unlike the Philippines which have had public clashes with China in the disputed area, Malaysia’s government prefers diplomatic channels. It rarely criticises Beijing publicly, even though Chinese coast guard ships have sailed near Malaysia’s waters.

This is partly to protect economic ties as China has been Malaysia’s top trading partner since 2009.

The ministry said Malaysia and China were committed to peaceful settlements, without any recourse to disputes and violence.

The two countries became co-chairs last month for a three-year period of the Association of Southeast Asian Nations (ASEAN).