China is committed to properly managing differences through dialogue and consultations, but its "tolerance does have a limit", a Chinese Defense Ministry spokesman said on Thursday regarding the Philippines' recent provocations in China's Xianbin Reef in the South China Sea.

The spokesman, Senior Colonel Wu Qian, made the remarks at a news conference in Beijing, criticizing the Southeast Asian country's efforts to seek long-term existence in the uninhabited reef by illegally anchoring a vessel there.

In April, Philippine coast guard ship No 9701 entered the lagoon of Xianbin Reef and has been anchored there since.

Chinese authorities closely monitored and managed an illegal resupply mission by a Philippine H-145 helicopter on Wednesday near the Xianbin Reef, China Coast Guard spokesman Gan Yu said late on Thursday.

Gan said the helicopter had attempted to deliver supplies to a Philippine coast guard vessel unlawfully stationed in the area. He warned that this risky maneuver by the Philippines could result in unforeseen maritime and aerial incidents.

He noted that the Philippines had recently tried and failed to resupply the No 9701 ship using watercraft such as coast guard ships, government vessels and fishing boats.

The spokesman said that the No 9701 ship is operational and capable of leaving independently. But the Philippines has chosen to endanger the crew's health and safety, using "humanitarianism" as a pretext for reckless rights violations.

A spokesperson for the Armed Forces of the Philippines said that the maneuvers by the Chinese undermined the safety of the Philippine crew members and violated international law, according to media reports.

Wu, the defense ministry spokesman, rebutted the claims, saying that China has indisputable sovereignty over Nansha Islands, including Xianbin Reef, and its adjacent waters.

The Philippine ship's intrusion has seriously violated China's sovereignty, breached international law and the stipulations of the Declaration on the Conduct of Parties in the South China Sea, and undermined regional peace and stability, Wu said.

"The Chinese side firmly opposes those activities and has lodged solemn representations multiple times", said Wu, stressing that the Philippines' attempt to seek a permanent presence at Xianbin Reef is akin to opening a "Pandora's box" and has drawn strong opposition from regional countries.

Since Aug 19, Philippine coast guard ships have repeatedly intruded into the adjacent waters of Xianbin Reef, and deliberately took dangerous maneuvers to ram China Coast Guard vessels, the ministry spokesman said.

"The Chinese side took necessary measures in accordance with the law," he said, adding that the responses "were professional and appropriate".

"The Chinese side is committed to properly managing differences through dialogue and consultations, but our tolerance does have a limit," Wu said.

The official urged the Philippines to withdraw its ship and personnel as soon as possible, and restore the unoccupied status of Xianbin Reef with no infrastructure, warning that China will continue to take resolute and strong measures to safeguard the nation's territory and maritime rights and interests.

The spokesman also responded to recent comments by United States officials claiming that a Mutual Defense Treaty between the Philippines and the US applies to armed attacks on Philippine armed forces, public vessels or aircraft anywhere in the South China Sea.

Wu said that no country is able to surpass the US in stirring up trouble or disrupting peace and stability in the South China Sea.

"It is the US' support and endorsement that have emboldened the Philippine side in making reckless provocations time and again," Wu noted.

He said that intimidating China with the Mutual Defense Treaty will never work.

"On the contrary, it will only result in stronger indignation and greater morale among the Chinese people," he stressed.

Contact the writers at jiangchenglong@chinadaily.com.cn