China and Australia exchanged accusations on Monday after an encounter over the disputed South China Sea, with the PLA’s Southern Theatre Command Air Force saying that it drove away a P-8A military aircraft that illegally intruded into Chinese airspace.

“The People’s Liberation Army Southern Theatre Command organised naval and air forces to track and monitor the intruder in accordance with regulations, implement effective countermeasures, and issue warnings to drive it away,” Senior Colonel Li Jianjian, a spokesperson for the command, said in a statement.

Li said the incident happened in airspace over the Paracel Islands, which are known as the Xisha Islands in China.

“Australia’s actions seriously infringed upon China’s sovereignty and could easily trigger maritime and aerial incidents,” Li said, adding that the command warned Australia to immediately cease its “provocations”.

“Our forces remain on high alert at all times and will resolutely defend national sovereignty, security and regional peace and stability.”

The statement came after Australia’s defence ministry on Monday said it expressed “concerns” to Beijing over the “unsafe and unprofessional” manoeuvres of a PLA Air Force jet over the South China Sea, accusing the crew of releasing flares close to an Australian patrol aircraft.