China is sending more ships to Vietnam’s exclusive economic zone (EEZ), and the frequency and length of those trips, which have picked up since early May, is raising tensions in the South China Sea.
After a nearly monthlong incursion of a survey ship and its large entourage, more Chinese vessels are sailing through sensitive locations within Vietnamese waters. Vietnam’s EEZ extends out 200 nautical miles from the country's coast.
The presence of Chinese research, coast guard and civilian ships in these waters, in addition to harassing Vietnamese oil and gas operations, showcases Beijing’s push of contested claims in the resource-rich waters, experts say.
Hanoi rejects Beijing’s "nine-dash line," a map demarcation that China uses to claim near-total jurisdiction over the South China Sea, and that sentiment is apparently not limited to government officials.
"China thinks they are stronger, they are better, so they have the right to trespass anywhere they want in the East Sea even though they know it's illegal," a 26-year-old living in Ho Chi Minh City told VOA, requesting anonymity because of potential repercussions for discussing political matters and using the Vietnamese term for the sea.
"The conflict between Vietnam and China is a political hot potato," he said.
Ray Powell, who leads Stanford University's Project Myoushu on the South China Sea, told VOA last month that China's intrusion "has become routine."
"China wants to normalize it to the point that Vietnam no longer reacts or protests," he said.
On June 10, China's patrol ship Zhong Goo Yu Zheng 310 and a luxury passenger vessel, San Sha 2 Hao, sailed through Vietnam's EEZ near oil and gas fields close to Vanguard Bank, a Vietnamese outpost and flashpoint between the countries. In 2019, a China coast guard contingent and Chinese survey vessel operated around Vanguard Bank, resulting in a monthslong standoff between Vietnamese and Chinese coast guards and diplomatic outcry.
Vietnam, international backlash
"They spent about 30 hours in Vietnam's EEZ, mostly in and among its oil and gas operations," Powell wrote. "[It's] simply communicating to Hanoi that China has 'jurisdiction' over these waters."
This was far from the only recent incursion.
The world's largest coast guard vessel, China coast guard ship 5901, was active near Vanguard Bank on June 8.
China's coast guard ship 5403 was also operating near oil drilling initiatives in Vietnam's EEZ from May 23 to June 4.
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In the most "heavy handed" intrusion since 2019, according to Powell, the Chinese research vessel Xiang Yang Hong 10 operated in the country's EEZ for nearly a month. From May 7 to June 4, the research vessel – flanked at times by as many as 12 ships – operated primarily around joint oil and gas operations led by Russian and Vietnamese firms.
Although countries are allowed through foreign EEZs, unauthorized surveys are not and are considered hostile if done without prior notice.
Oddities in Xiang Yang Hong 10's route pointed to Beijing's assertion of its disputed jurisdiction. During the four-week stretch, the research ship would go to China's Fiery Cross Reef, before returning to Vietnamese waters. Instead of taking a direct route, the vessel used a northeastern path that took it approximately 85 nautical miles away from Nha Trang, a city on Vietnam's south-central coast.
"It was just one more way that they showed they can cross Vietnam's EEZ whenever they want to, " Powell said. "There's no reason to go past there other than sending a message."
Beijing's aims, Hanoi's response
While intimidating energy exploration is the most obvious aim, it is seen as likely just part of Beijing's overall agenda.
"Exploring the deep South China Sea has become China's strategy for obtaining valuable information for economic development and military intelligence," wrote Vietnam-based researcher Van Pham, head of the nonprofit South China Sea Chronicle Initiative, which monitors maritime traffic.
China has been rotating research and survey vessels in foreign EEZs in the South China Sea consistently, Pham said. Coast guard ships also operate at sensitive locations in disputed territory "on a daily basis," Pham added, and the organization has observed Chinese fishing boats near Vietnam's oil and gas blocks.
Vietnamese fishermen are often caught up in the conflict. Between 2014 and 2022, 98 Vietnamese boats were destroyed by Chinese vessels.
Responding to China's intrusion is a tricky balancing act for Hanoi, said Nguyen The Phuong, an international relations lecturer at the Ho Chi Minh City University of Economics and Finance.
"Any small misstep on the Vietnamese side could escalate the conflict," Phuong said. "It is extremely difficult."
Call for 'respect'
At a May 18 press conference, Hanoi made a rare statement in response to the monthlong intrusion of Xiang Yang Hong 10.
Vietnamese Foreign Ministry spokesperson Pham Thu Hang urged China to withdraw the research vessel, coast guard and fishing boats and "respect Vietnam’s sovereignty and jurisdictional rights."
"Vietnam needs to be very careful on how to protect its sovereignty from the outside and from the inside how to manage nationalism in a way that it could not damage the state's legitimacy," Phuong said.
This discord is likely to increase.
"This will happen in the future again [and will be] much more intense," Phuong said.
For now, a 28-year-old Ho Chi Minh City native is confident the Vietnamese government is doing enough to maintain stability.
"The Vietnamese government will understand how to deal with these situations," he said, requesting anonymity because of the sensitivity of the topic. "I think the Vietnamese government is good at dealing with them to avoid war."