Analysts believe the purges are designed both to reform the military and to ensure loyalty to Chinese leader Xi Jinping, who also chairs the military commission.
Chinese authorities said they had rescued 15 people after the ship with 21 Filipinos on board capsized near Scarborough Shoal, the subject of a territorial dispute with the Philippines.
Organizers of what was once an annual commemoration of China’s 1989 crackdown on pro-democracy protesters face up to 10 years in prison under the Beijing-imposed law.
Chinese exports to the U.S. suffered after President Donald Trump began raising tariffs last year, but the decline was offset by shipments to the rest of the world.