Joint naval exercises by the US, Japan, the Philippines and Australia on Sunday prompted China's military to respond with its own increased naval and air patrols in the South China Sea on Sunday.
“The Southern Theatre Command of the People’s Liberation Army will conduct a joint air and sea combat patrol in the South China Sea on April 7,” the Southern Theatre Command announced on Sunday morning.
The command noted that the military activities “intended to sabotage the situation” and create “hotspots” in the waters were “well under control”.
The US, the Philippines, Japan and Australia had announced on Saturday that they would conduct a “maritime cooperative activity” on Sunday within what they referred to as the “Philippine exclusive economic zone”. This is the first in a series of such activities involving naval and air forces in waters claimed by both China and the Philippines.
Japan deployed its destroyer, the JS Akebono, which included anti-submarine warfare training. Philippine warships, the BRP Gregorio del Pilar and BRP Ramon Alcaraz, joined the American USS Mobile and the Australian HMAS Warramunga, according to the Japanese Embassy in Manila.
The purpose of the drills, according to a joint statement by the four allies, is to "uphold the right to freedom of navigation and overflight." US Defense Secretary Lloyd Austin and his three counterparts reiterated that their countries view the 2016 international arbitration ruling against China as "a final and legally binding decision on the parties to the dispute."
The ruling, issued by a tribunal in The Hague, found that China's so-called "nine-dash line" is invalid under international law. Dating back to the late 1940s, China has claimed that its "nine-dash line" demarcation gives it control over about 90% of the resource-rich South China Sea. However, there are overlapping claims by Vietnam, Malaysia, Brunei, Indonesia, and the Philippines. Chinese officials have refused to accept the 2016 ruling, saying it has no jurisdiction over the issue.
Tensions have risen between Beijing and Manila over the disputed waters in the South China Sea. The Philippines - a key US ally in the region that hosts its military bases - accused Chinese ships of conducting “dangerous” maneuvers.
Beijing, in turn, claimed that the Philippines was "roping in non-regional countries" to inflame tensions. China has also repeatedly warned that joint US military exercises undermine its security interests.