MANILA • Malaysia and the Philippines have decried continued incursions by Chinese vessels in areas of the South China Sea they claim as their own in yet another sign of continuing tensions in the disputed waters.

The Philippine Department of Foreign Affairs said it protested against provocative actions by Chinese government vessels that used "the unlawful issuance of over 200 radio challenges, sounding of sirens, and blowing of horns" against Philippine authorities that were "conducting legitimate, customary and routine patrols".

"These provocative acts threaten the peace, good order, and security of the South China Sea and run contrary to China's obligations under international law," the agency tweeted on Wednesday.

Tensions between the two nations over the disputed sea have escalated over the past months, with the Philippines repeatedly protesting against the presence of Chinese ships in the area.

Manila has been backed by the US, while Beijing has said its actions were normal and legitimate.

Malaysia's Foreign Minister Saifuddin Abdullah warned separately during an event on Wednesday that his country could see more Chinese ships in its maritime territory so long as state-owned Petronas continues developing the Kasawari gas field located within its exclusive economic zone off the coast of Sarawak.

Earlier this month, Malaysia summoned China's ambassador for the second time this year over the presence of ships in its territorial waters. Prime Minister Ismail Sabri Yaakob warned there would be no compromises if a threat in the South China Sea materialises.

"I have lost count the number of protest notes we have sent to China," Mr Saifuddin said. "We will be steadfast and continue to respond diplomatically to them."

China's Ministry of Foreign Affairs reiterated its position at a regular news briefing in Beijing yesterday. "China's position on the South China Sea issue is consistent and clear, and our maritime law enforcement departments have followed Unclos and other international law to have operations that defend our rights," spokesman Wang Wenbin said, referring to the United Nations Convention on the Law of the Sea. "That is legitimate and justified."

BLOOMBERG