MANILA - The Philippines has resumed stamping Chinese passports with pages that bore a faint map showing Beijing's expansive claim over the disputed South China Sea.
Immigration Commissioner Jaime Morente said this arose from "security concerns" and was not a diplomatic retreat.
The Philippines stopped stamping Chinese passports in 2012 after it was caught in a months-long stand-off with China over a disputed shoal in the South China Sea.
At the time, China introduced a new type of passport with the historic nine-dash line that marks its claim to almost all of the South China Sea, including waters that the Philippines considers part of its territories. Brunei, Malaysia, Vietnam and Taiwan also claim waters that lie within the contentious line.
Refusing to endorse the passport as doing so could be "misconstrued as legitimising the nine-dash line", Philippine immigration officials were instead ordered to stamp a separate sheet of paper inserted into Chinese passports.
Mr Morente said the practice presented "security concerns". "Sheets of paper can easily be lost," he added.
In 2013, a year after it stopped stamping Chinese passports, the Philippines sued China. Three years later, an international arbitration court in The Hague sided with Manila, ruling that the nine-dash line claim has no legal basis.
The dispute is likely to play out further in the pages of Chinese passports.
Foreign Affairs Secretary Teodoro Locsin in August said that the Philippines' visa stamp would feature a map showing the country's exclusive economic zone "to its widest extent". "So tit for tat," he said in a Twitter post.
Last month, Mr Locsin called for a boycott of the DreamWorks movie Abominable, which has a brief scene that shows a map that includes the nine-dash line.
China's map on its passport has no "legal effect" and "is for propaganda purposes only", Mr Jay Batongbacal, director of the University of the Philippines' Institute for Maritime Affairs and Law of the Sea, told ABS-CBN News. "It's fair game," he said.
For now, the Philippines' policy reversal is in line with President Rodrigo Duterte's efforts to improve ties with China.
China has rewarded his administration with pledges of billions of dollars' worth of investments, and by importing Philippine fruits and sending over Chinese tourists, whose numbers nearly tripled to 1.3 million last year from 2015.
Critics, however, accuse Mr Duterte of weakening Manila's position in the South China Sea. Much of the assistance that China promised has also yet to materialise, they said.
But Mr Duterte maintains that the South China Sea issue requires a "delicate balancing act".
