Reuters quoted a statement late on June 1 from the Malaysian Foreign Ministry saying that the Malaysian air force closely monitored the aircraft of the Chinese People's Liberation Army Air Force in Malaysian waters on May 31.
Malaysian Foreign Minister Hishammuddin Hussein said the ministry would send a statement of protest to Beijing and the Chinese Ambassador to provide an explanation regarding Malaysias sovereignty and airspace violations.
M Malaysias view is very clear having friendly diplomatic relations with any country does not mean that we will harm our national security, said Hishammuddin.
The Malaysian Air Force discovered Chinese aircraft flying in a "tactical formation" at an altitude of 7,000 to 8,230m on the morning of May 31 off the coast of Borneo. The Malaysian Air Force has deployed a number of aircraft from the air base in Labuan to perform visual identification of Chinese aircraft - and confirmed that these are the Ilyushin-76 and Xian Y-20 transport models.
"This incident is a serious threat to national security and flight safety," the Malaysian Air Force said in a statement.
The Chinese Embassy previously said that the aircraft were flying periodically and " strictly complying" with international law without violating the airspace of other countries.
Reuters quoted a Chinese spokesperson as saying: "China and Malaysia are two friendly neighbors and China is ready to continue bilateral friendly consultations with Malaysia to maintain peace and stability in the region."
According to Al Jazeera, Malaysia's opposition party Pakatan Harapan said the incident was "concerning" and urged the government to issue a "clear action plan" on how to deal with such activities.
Last year, Malaysia opposed China after discovering that the Chinese ship Haiyang Dizhi 8 was conducting a survey near a survey ship of Malaysia's state oil and gas company Petronas.
