Philippine President Rodrigo Duterte's pivot toward China will come under the spotlight as he meets Chinese President Xi Jinping this week.

The Southeast Asian nation is a long-time ally of the U.S., but since Duterte took office in 2016, the Philippines' ties with China have been warming. Duterte's visit to China — from Aug. 28 to Sept. 1 — is his fifth in three years. He has not made a single trip to the U.S. as president.

But the Philippine public has grown increasingly critical of the president's Beijing-friendly stance. That's especially the case after a Philippine fishing boat collided with a Chinese vessel in June in an area of the South China Sea claimed by both countries.

Phil News Agency on Twitter: President Rodrigo Duterte says he is ready to bring up the arbitral ruling and the 60-40 sharing arrangement on the proposed joint exploration for oil and gas in the West Philippine Sea in his visit to China.

An international tribunal in The Hague had ruled in July 2016 that the area is an exclusive economic zone of the Philippines, but China rejected that verdict. Duterte's apparent refusal to enforce that ruling against Beijing — particularly after the June collision — contributed to anti-China protests in Manila in recent months.

Faced with mounting domestic pressure, the Philippine president said he will — for the first time — bring up the 2016 ruling when he meets the Chinese leader in Beijing. Analysts, however, aren't sure Duterte will go far enough to win over critics.

The Philippine president "emphasized he would only do this in a way that did not anger Beijing," which likely means it will be "his tone rather than policy stance" that's changing, Peter Mumford, practice head for Southeast and South Asia at risk consultancy Eurasia Group, wrote in a note last week.