The Philippine military has deployed a navy ship and air force planes to shadow a Russian submarine that passed through the South China Sea off the country's western coast.
The Russian submarine identified itself in response to a Philippine Navy two-way radio inquiry last week, saying it was en route home to Russia's eastern city of Vladivostok after joining an exercise with the Malaysian Navy, Jonathan Malaya, assistant director-general of the National Security Council, said.
The submarine, like other foreign ships, has the right of "innocent passage" in the country's exclusive economic zone (EEZ) but it still sparked concern when it was spotted on Thursday about 80 nautical miles (148 kilometres) off the Philippine province of Mindoro.
The submarine was sighted after it surfaced due to weather-related conditions.
"All of that is very concerning," President Ferdinand Marcos Jr told reporters when asked about the submarine.
"Any intrusion into the West Philippine Sea, of our EEZ, of our baselines is very worrisome. So, yes, it's just another one."
Mr Marcos used the Philippine name for the South China Sea, where his country plus Vietnam, Malaysia, Indonesia, and other coastal states have faced an increasingly aggressive China, which claims the busy waterway virtually in its entirety.
[MAP]An alarming spike in territorial confrontations, particularly between Chinese and Philippine coast guard and naval forces, starting last year has prompted closer surveillance by the United States and other Western governments of the key global trade route.
Chinese helicopters fly close to fishing boats
The Philippines coast guard said on Monday that a Chinese military helicopter flew close to fishing boats manned by Filipinos in a "dangerous act of harassment" last week at Iroquois Reef, a disputed fishing area in the South China Sea.
Two Philippine coast guard patrol ships have been deployed to the area to protect Filipino fishermen, coast guard spokesperson Commodore Jay Tarriela said.
Chinese officials described its actions as "control measures".
"Recently, several Philippine ships … illegally gathered under the pretence of fishing in the waters near Houteng Reef of China's Nansha Islands," China Coast Guard spokesperson Liu Dejun said in a statement, using the Chinese names for the Iroquois Reef and the Spratly Islands.
"The Chinese Coast Guard took necessary control measures against the Philippine ships in accordance with the law," Liu said.
"We warn the Philippine side to immediately stop its infringements and provocations."
China claims almost all of the South China Sea, despite an international ruling in 2016 concluding its claims have no legal basis.
Beijing has deployed navy, coast guard, and so-called maritime militia forces — allegedly Chinese fishing vessels — in a bid to bar the Philippines from strategically important reefs and islands in the South China Sea.
Vessels from the two sides have clashed frequently in the past year, resulting in injuries and damages.
AP/ABC
