Malaysia is now investigating the release to a Philippine media of a sensitive diplomatic note it received from China regarding the South China Sea in another known leak involving Beijing.
Malaysia's Foreign Ministry said it views the leak of such a document "with grave concern" as it constitutes an official communication channel between the two countries.
"In this context, the Ministry is conducting an internal investigation into this breach of classified information," it said in a statement dated Sept. 4.
"The Ministry will also file a police report to enable an investigation by the relevant authorities to be undertaken promptly," it added.
On Aug. 29, a Philippine media learned from a leaked diplomatic note that even Malaysia got a taste of China's bullying when Beijing told them that it was infringing on the Chinese nine-dash line.
In May, the Chinese Embassy in Manila also shared with Manila Bulletin a wiretapped conversation between its diplomat and a military official regarding the South China Sea, which the Philippine government saw as a breach of diplomatic agreement and a violation of local law.
China reportedly expressed serious concern and strong dissatisfaction over Malaysia's actions.
In its statement, Malaysia said it remains committed and determined to resolve its South China Sea dispute with China peacefully through consultations and dialogue, without recourse to dispute or violence.
"Malaysia's stance on the South China Sea remains unchanged," it said.
Kuala Lumpur claims Raja Jarum, a part of the South China Sea that China entirely claims to be its own.
"Malaysia will continue to defend its sovereignty, sovereign rights, and interests in its maritime areas based on the 1979 Malaysia Map. This approach aligns with the universally recognized principles of international law, including the United Nations Convention on the Law of the Sea (UNCLOS)," it added.