MANILA (REUTERS) - The Philippines condemned "in strongest terms" the actions of three Chinese Coast Guard vessels which blocked and used water cannons on two Manila supply boats on their way to a Philippine-occupied atoll in the South China Sea, its top diplomat said on Thursday (Nov 18).
Foreign Affairs Secretary Teodoro Locsin said no one was hurt during the Nov 16 incident at the Second Thomas Shoal but the Philippines boats, which were transporting food supplies to military personnel based there had to abort their mission.
"The acts of the Chinese Coast Guard are illegal," he said in a statement, reminding China that a public vessel is covered by the Philippines-United States Mutual Defence Treaty.
Mr Locsin said he had conveyed "in the strongest terms" to the Chinese Ambassador to Manila "our outrage, condemnation and protest of the incident".
He warned Beijing's "failure to exercise self restraint threatens the special relationship" between the two countries.
"China has no law enforcement rights in and around these areas. They must take heed and back off," Mr Locsin said.
The office of President Rodrigo Duterte, who has been a staunch supporter of China, said it was aware of the incident at the shoal.
"We will continue to assert our sovereignty, sovereign rights, and jurisdiction," acting spokesman Karlo Nograles said.
Before the incident, National Security Adviser Hermogenes Esperon said authorities had noticed an unusual presence of Chinese maritime militia near the atoll and Philippine-occupied Thitu island. China has denied operating a militia.
There were 19 vessels near Second Thomas Shoal last week, and 45 near Thitu Island, Mr Esperon told reporters, describing those as "very aggressive".
Manila regards Second Thomas Shoal, which lies 105 nautical miles (195km) southwest of the Philippine region of Palawan, as being within its 200-nautical mile exclusive economic zone. It has occupied the shoal since 1999 after intentionally grounding a navy ship on the reef.
China says the reef is part of its territory as it falls within the "nine-dash line" that it uses on maps denoting its claim to almost the entire South China Sea, but a 2016 ruling by Permanent Court of Arbitration in The Hague found in favour of the Philippines.
The Chinese embassy in Manila did not immediately respond to requests for comment from the media.
China claims sovereignty over vast swathes of the South China Sea, but Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have lodged competing claims for some or all of the islands.