MANILA -- Beijing exhibited double standard in sending warships to Philippine waters without informing Manila, which violates its safety regulations, a maritime law expert said Thursday.
China requires foreign warships exercising innocent passage to seek its consent before entering its territorial seas, said Jay Batongbacal, director of the University of the Philippines (UP) Institute for Maritime Affairs and Law of the Sea.
"The entry of Chinese warships into Philippine waters without prior notice and consent of the Philippines runs counter to their own policy for their own waters, and thus demonstrates a double standard at the very outset," he said in a Facebook post.
Five Chinese warships passed the Sibutu Strait in the Philippines' southern tip last July and earlier this month without informing local authorities, the military said Wednesday.
The incident cannot be considered an innocent passage because the trips moved in a zigzag path, said Lt. Gen. Cirilito Sobejana, commander of the Armed Forces of the Philippines' Western Mindanao Command.
Under the United Nations Convention on the Law of the Sea, a foreign vessel may be allowed to cross a coastal state’s territorial waters without prior notification if the ship is conducting innocent passage or movement in a straight path heading back out to sea.
Batongbacal added that the Chinese ships' excursion into Philippine waters cannot be deemed innocent passage if their weapons were active or they were part of a larger military exercise, which is difficult to determine based solely on the photos released by the military.
Sibutu Strait is covered by a trilateral cooperation agreement among the Philippines, Malaysia and Indonesia, which required all vessels to pass through "navigational corridors" to enhance the security of the area that is fraught with risks of piracy, sea robbery and terrorism, added Batongbacal.
Warships "normally abide by such rules in order to avoid untoward incidents and endangering the safety of navigation," he said.
"The Chinese warships' actions of passing through without even acknowledging the Philippine queries therefore runs counter to the Philippines' legitimate maritime safety regulations."
Batongbacal also warned that the Philippines "should expect more frequent passage of Chinese warships through its waters as China expands its naval reach."
The Philippines earlier filed a diplomatic protest against the passage of Chinese warships in its territory in 4 instances from February to July.
Beijing claims large parts of the South China Sea, where rich petroleum reserves are thought to sit deep beneath the waters, and through which roughly $3.4 trillion in shipping passes each year.
President Rodrigo Duterte last week said he will finally raise Manila’s 2016 arbitral victory, which invalidated Beijing’s sweeping maritime claims, when he visits China later this month.