Protesters in the Philippines have been burning Chinese flags recently in response to a collision in the contentious South China Sea.

According to Philippines Defense Secretary Delfin Lorenzana, on the night of June 9th, a Chinese fishing vessel crashed into a Filipino one near the Recto Bank, located about 150 kilometers from the Philippine island of Palawan.

The crash caused the Philippine boat to sink and the Chinese vessel is accused of leaving 22 crewmen in the water to drown. Fortunately, they were rescued by a nearby Vietnamese boat.

Philippine President Rodrigo Duterte has agreed with China’s view on the incident, calling it “just a collision,” a characterization that has angered some members of the public.

On Tuesday, around 50 Filipinos gathered at Manila’s Rizal Park to burn 22 Chinese flags made of paper, a number symbolizing the 22 fishermen left stranded at sea.

There was a similar demonstration staged last week to mark Philippines Independence Day.

WATCH: Protesters burn Chinese flag during Philippine Independence Day pic.twitter.com/lMJvTEoeIL — Rappler (@rapplerdotcom) June 12, 2019

Since taking office in 2016, Duterte has faced criticism for being “too soft” on China, particularly when it comes to the disputed South China Sea. Last year, he joked that the Philippines should be made a Chinese province.