By Wu Qiaoxi | 2025-03-07

China conducted live-fire military exercises in the Gulf of Tonkin from February 24 to 27 in a move widely seen as a response to Vietnam’s newly declared maritime baseline.

The People's Liberation Army (PLA) Southern Theater Command also dispatched naval and air forces to Scarborough Shoal on February 27 for combat readiness patrols.

The PLA later released a new video of the patrols on Chinese microblogging platform Weibo as a show of force, just a week after a tense aerial standoff between China and the Philippines in the same area.

Earlier, on February 21, Vietnam's Foreign Ministry announced a newly delineated maritime baseline in the Gulf of Tonkin, covering 14 coordinate points from the waters off Quang Ninh province to Quang Tri province.

The Vietnamese government said that the new baseline provides additional legal basis for "protecting and enforcing Vietnam's sovereignty."

For its part, China's Maritime Safety Administration stated that the military exercises in the Gulf of Tonkin were concentrated in the northern part of the gulf, near the Chinese side.

Escalating tensions

The sovereignty dispute between China and Vietnam centers on the Spratly Islands, the Paracel Islands and nearby waters.

Although both nations have maintained relative stability in the Gulf of Tonkin since a 2000 agreement, China's announcement of a new maritime baseline earlier last year prompted Vietnam to submit a revised delimitation proposal to the United Nations (UN) in July, citing the 1982 UN Convention on the Law of the Sea to define maritime boundaries.

A series of actions from both sides have escalated tensions in recent months.

In February, a report from China's Ministry of Natural Resources accused Vietnam of large-scale land reclamation on Barque Canada Reef in the Spratly Islands since 2022, expanding the reef 10-fold to 1.94 square km and dredging a channel capable of accommodating large warships.

China's Foreign Ministry condemned these activities in a news briefing, calling them an expansion on "illegally occupied" reefs.

However, China's own land reclamation has been even more extensive, with 16 artificial islands built over the past decade

According to a report by the Center for Strategic and International Studies, China is responsible for 65% of coral reef destruction in the South China Sea, the highest among all involved nations.

Diplomatic strategy

Despite increasing sovereignty disputes, Vietnam has been restrained in its response because of its close economic ties with Beijing.

China is Vietnam's largest trading partner, with growing cooperation in infrastructure and investment.

On February 19, Vietnam's National Assembly approved an $8 billion Chinese loan to build a 390.9km-long railway across nine provinces, from Lao Cai to Haiphong via Hanoi.

Meanwhile, Chinese companies are shifting operations to Vietnam to bypass the US-China trade war. According to the Financial Times, new Chinese investments now make up nearly one-third of the total in Vietnam.

Vietnam's diplomatic strategy seeks a delicate balance by strengthening security cooperation with the United States, Japan, Australia and other nations.

Recently, Vietnam upgraded its relationship with New Zealand to a comprehensive strategic partnership.

New Zealand Prime Minister Christopher Luxon was considering deploying a naval vessel to the South China Sea later this year to enhance cooperation with Vietnam and contribute to stability, security and peace in the Indo-Pacific region, the New Zealand Herald reported February 26.