Chinese vice foreign minister Fu Ying said Beijing was ready for "any escalation" of a tense maritime standoff with the Philippines over a disputed shoal.
The month-long flare-up is one of the most high-profile incidents for years between the two countries over their competing territorial claims to parts of the South China Sea, which is believed to sit atop vast oil and gas deposits.
"The Chinese side has... made all preparations to respond to any escalation of the situation by the Philippine side," Fu told a Philippine diplomat Monday, according to a statement posted on China's foreign ministry website Tuesday.
The two countries have been locked in the row since April 8, when Beijing's vessels blocked a Philippine warship from arresting crews of Chinese fishing boats near the disputed Scarborough Shoal -- or Huangyan island in Chinese.
Both Beijing and Manila have ships in the area, racking up tensions in the region.
Currently, four Chinese surveillance ships and 10 fishing boats have anchored off the disputed shoal, facing off against two Philippine coastguard ships and a fisheries bureau vessel.
On Monday, Fu summoned Alex Chua, charge d'affaires at the Philippine embassy in China, so that she could make a "serious representation" over the situation, according to the statement.
"It is obvious that the Philippine side has not realised that it is making serious mistakes and instead is stepping up efforts to escalate tensions," she told him.
"The Philippine side... repeatedly made erroneous remarks which misled the public in the Philippines and the international community, played up the public feelings, thus severely damaging the atmosphere of the bilateral relations between China and the Philippines.
"Therefore, it is hard for us to be optimistic about the situation."
The Philippines argues the shoal is well within the country's 200-nautical-mile exclusive economic zone, as recognised by international law.
But Beijing claims almost the whole of the South China Sea as its historical territory, even waters close to other countries' coasts and hundreds of kilometres from its own landmass.
Manila last week vowed to show restraint in the standoff.
"We do not wish to escalate any tensions right now," President Benigno Aquino's spokesman told reporters.
"Therefore, what we're doing for now is to just to document the situation... and consequently, raise it before the (international) tribunals."
Fu said Monday Chinese government vessels would "continue to be on alert" near the shoal and urged the Philippines to withdraw its own ships, but she stressed Beijing still wanted to seek a diplomatic solution to the crisis.
A commentary in the overseas version of the People's Daily -- the ruling Communist Party's mouthpiece -- concurred, but warned that the Philippines should not "view China's goodwill as a sign of weakness".
"We have enough wisdom and means when facing with such rivals to subdue the enemy without fighting and make them stop," it said.