It's the second time in two months a Vietnamese vessel has been rammed.
A Chinese Coast Guard cutter sank a fishing boat on April 2. Beijing insisted the Vietnamese craft had rammed the Chinese ship and sunk itself.
But South China Sea nations – including the Philippines, Taiwan, Borneo and Malaysia – are concerned the latest incident broadcasts a new willingness to enforce Beijing's arbitrary "fishing ban".
'FLASHING SWORD 2020'
Beijing has been declaring a unilateral summer fishing ban over the South China Sea for several years.
It wants regular halts in all fishing activity above the 12th parallel (which encompasses the Paracels) to allow fish stocks to recover. As it has no internationally recognised jurisdiction over the sea, neighbouring countries have been mainly ignoring the proclamation.
For its part, Beijing has generally not been enforcing the ban on foreign-flagged vessels.
The problem is, this area includes vast tracts of water recognised by the United Nations as belonging to the Exclusive Economic Zones (EEZs) of Vietnam and the Philippines in particular.
Both nations have again rejected Beijing's claim of authority over their resources.
But this year, Beijing's Ministry of Agriculture and Rural Affairs declared China's Coast Guard would engage in operation Flashing Sword 2020 to enforce the ban.
Captain Nguyen Loc told Vietnamese state-controlled media he refused to sign a confession he had breached Chinese waters.
"I steered the boat to escape, and the Chinese ship number 4006 pressed from behind and sunk us. My men quickly jumped to the water. I was still sitting in the cabin, and the water was up to my chest. We shouted 'Murderers! Murderers!'"
The Coast Guard vessel then reportedly deployed a motorboat to recover some crew and return them to their flooded vessel.
"When boarding the Chinese vessel, they demanded that I sign a piece of paper or they would beat me. When they struck, I noticed that the large ship had two big guns ready. I was kicked 30 or 40 times, and hit about 20 times," Loc said.
"They told me to ask my companions (other fishing boats) to tow my boat home and that this is not their problem. I asked them to tow us to the shoal to fix the boat, but they refused. They then beat me up and left."
GROWING DEFIANCE
Vietnam this year openly rejected Beijing's fishing ban. On April 4, it lodged an official complaint about the sinking of its fishing boat.
According to Dr Nguyen Thanh Trung of the Saigon Centre for International Studies (SCIS), this open defiance has come as something of a surprise to the Chinese Communist Party.
"Beijing must have thought that the region would be caught off-guard. However, China's sinking of the fishing vessel has had a much bigger impact than what it likely anticipated," he writes.
That incident drew international condemnation.
This incident threatens more of the same.
"China's coercion has also unintentionally helped to unite smaller claimants in the South China Sea," Dr Trung says. He points to vocal support and sympathy from the Philippines which has also experienced attacks on its fishing fleet in recent years.
"It is likely that China sees the COVID-19 pandemic as a rare opportunity to advance its territorial interests," he says, pointing to aggressive moves by Chinese survey ships, coast guard vessels and navy ships in recent months.
"If China keeps pushing hard with its bullying behaviour in the South China Sea, it will certainly give a boost to rising anti-China sentiment in Vietnam, which in turn puts pressure on Vietnamese leaders to recalibrate their foreign policy when the Communist Party's National Congress convenes early next year."
