China "must be prepared" for any military confrontation in the South China Sea, the country's Global Times newspaper said in an editorial Tuesday.
Manila is contesting China's expansive territorial claims in the South China Sea, which the Philippines contends are invalid under international law.
China however has said the arbitration tribunal has "no jurisdiction" over the matter and will resolve such disputes directly with the countries involved.
Control of the region is valuable because more than $5 trillion worth of global trade passes through the South China Sea each year, and China has been accused of ramping up tensions over control in recent years by building artificial islands on reefs, on which it has added airstrips and other military-style installations.
Global Times said the dispute had been "greatly complicated" by heavy U.S. intervention and the involvement of the international tribunal.
"Washington has deployed two carrier battle groups around the South China Sea, and it wants to send a signal by flexing its muscles: As the biggest powerhouse in the region, it awaits China's obedience," said the paper.
"If the US is taking advantage of the mess to deploy more military forces to the South China Sea, which are a direct threat to China's national security, China's military exercises could be regarded as a countermeasure," it added.
China should speed up the development of its military capabilities as a result, it said.
"China is a peace-loving country and deals with foreign relations with discretion, but it won't flinch if the U.S. and its small clique keep encroaching on its interests on its doorstep."
China bases its territorial claim on a so-called "nine-dash line" that it has drawn over most of the resource-rich South China Sea.
"It is worth pointing out that China's territorial sovereignty and relevant rights over the South China Sea, which are firmly grounded on historical and legal evidences, have been formed over the long course of history and upheld by successive Chinese governments. China's sovereignty and rights and interests in the South China Sea are not subject to illegal rulings," said foreign affairs spokesman Hong Lei on Monday at the ministry's press conference.
To read the full Global Times editorial, click here.