Nguyen Thanh Bien winced as he rubbed his side, turning toward a portrait of Ho Chi Minh in a living room filled with conch shells. He said he was still dealing with internal injuries two weeks after Chinese authorities boarded his fishing boat and bashed him with iron pipes in a patch of the South China Sea claimed by both China and Vietnam.

"I got hit first in the head from behind — I was running to the front of the boat,” he said, sitting beside his father, who taught him to fish near their home on Vietnam’s south-central coast. "With the second blow, I lost consciousness.”

When he awoke, his catch, worth nearly $8,000, was gone. His ribs were broken. And three other crew members were injured.