Indonesia defied Chinese strictures on Thursday as it held a large-scale exercise in South China Sea, heightening concerns over worsening regional stability.
Jakarta's show of strength was held close to the waters claimed by China, and it came close on the heels of the Philippine president suggesting his country would drift away from treaty ally US.
Indonesian President Joko Widodo watched the drills from Ranai, the capital of the Natuna Islands archipelago, Reuters reported. As many as 70 military aircraft participated in the drills that showcased bomb-dropping manoeuvres as well.
Widodo's presence meant Jakarta was intent on delivering a strong message to Beijing, officials said. Indonesian navy and Chinese fishing boats have been involved in numerous confrontations in recent past around the disputed waters.
China lays claim to the whole of the South China Sea, saying the Paracel and Spratly island chains are integral part of the empire from ages.
Though China has disputes with countries such as the Philippines, Malaysia, Vietnam and Brunei over maritime borders in the South China Sea, Indonesia has traditionally played the role of an intermediary.
However, in late March, Indonesia had said itwould summon Chinese ambassador over a maritime standoff involving Chinese coast guards and Indonesian officials in an area known as the Natuna Sea near the disputed waters of the South China Sea.
In June, Indonesian President Joko Widodo visited Natuna in Riau Islands and held a cabinet meeting in a warship, sending a clear message about Indonesia's pledge to protect its sovereignty over areas it claims in the disputed waters.
Officialy, Jakarta termed Thursday's exercise as 'routine'. "The president has a policy that all the outer islands that are strategic will be strengthened, be it air, maritime or land," Gatot Nurmantyo, commander of the Indonesian National Armed Forces, said.
"Our country needs to have an umbrella. From corner to corner, we have to safeguard it."
Taiwan, Malaysia, the Philippines, Vietnam and Brunei have claims to a clutch of islands, shoals, rocky outcrops, atolls and sandbanks in the sprawling south China sea, making it a theatre of tense maritime dispute.
While China does not officially dispute Indonesia's claims to the Natuna islands, it has said two countries had "overlapping claims" in the region, causing Jakarta's ire.