In what may be a not-so-stealthy message to Beijing amid citizen protests of China's growing influence in its country, Vietnam has ordered a small fleet of silent Russian attack submarines.
Foreign policy experts say Vietnam's national identity is bound up in the idea of opposition to China, and the deal to buy the subs is the latest sign that the country of 87 million is concerned about "Sinification."
"The Vietnamese government is committed to a normal relationship with China, but nobody in Vietnam sleeps with their China eye closed," said Brantly Womack, professor of foreign affairs at the University of Virginia.
"A good part of Vietnam's patriotic identity is its righteous resistance to China."
Vietnam's $1.8 billion deal with Russia for six Kilo-class submarines is a substantial order for the tiny, struggling country, whose annual military budget is estimated at just $3.6 billion, according to Jane's Intelligence Review.
While not a signal of an arms race, "it's something that is pretty clearly a response to Chinese buildups" of force in the area, said Womack — including China's new submarine base on Hainan Island, just off the Vietnamese coast.
That resistance has been in ample evidence in recent weeks as Vietnamese workers have led protests against Chinese industrial projects they say could wreak havoc on their nation's central highlands.
Vietnam holds one of the world's largest reserves of bauxite ore, an ingredient used in making aluminum, and one that China needs to feed its voracious construction industry.
A recent decision by the Vietnamese government to allow the Aluminum Corporation of China to mine the ore prompted a widespread outcry over potential environmental harm, but also gave voice to significant fears of growing Chinese influence in the region.
A prominent Vietnam War-era general, Vo Nguyen Giap, is leading the charge against Chinese development. Giap, the founding father of Vietnam's military, wrote a public letter last month opposing the mining operation, and he reiterated his opposition Thursday as Vietnam's prime minister, Nguyen Tan Dung, visited his home.
"This is a strategically important location for the country in terms of security and defense, not only for Vietnam but all of Indochina," Giap told the prime minister, Reuters reported.
Some regional analysts say that tensions between Vietnam and China wax and wane over time, and that they are no higher than usual. The financial crisis has highlighted certain disputes, particularly the struggle to attract foreign investments.
"I don't at this point at least see any fundamental shift toward antagonism," said Ken Lieberthal, a visiting fellow in foreign policy at Brookings Institution. "There's always a limit to how much they trust each other."
Vietnam and China, which have been at odds for 3,000 years, most recently fought a brief but bloody war in 1979 that killed tens of thousands. The countries partnered during North Vietnam's war with French- and American-supported South Vietnam, but the partnership quickly dissolved after the North and South consolidated, and Vietnam sought closer ties with the Soviet Union in the late 1970s.
Lieberthal said that "real trouble" between Vietnam and China may lie in future disputes over water. China continues the heavy damming of the Mekong River, the lifeblood of Vietnam's south, which winds a 2,700-mile path through six countries but has its source in China.
"This affects people all along the Mekong. This is something that has tremendous popular resonance," Lieberthal told FOXNews.com. "If you're talking about a win-lose situation, the Chinese are in a position to win at tremendous cost to Vietnam and others."
The two countries are also engaged in disputes over two island chains in the South China Sea, the Paracels and the Spratlys, both of which are believed to hold substantial oil reserves.
Defense experts say the newly ordered Russian subs — called "Black Holes" by the U.S. Navy for their ability to avoid detection — are designed for anti-sub and anti-ship warfare. They could help protect Vietnam's claims in the South China Sea and deny access to its more than 2,000 miles of coastline.
U.S. officials were wary to comment on tensions in the region or on Hanoi's purchase of the vessels.
"We speak with all regional actors in the region including China and Vietnam on a regular basis regarding events and developments in the region," said State Department spokesman Gordon Duguid. "It's not useful for us to speculate on other nations' military purchases."