Chinese state media has warned US president Barack Obama not to meddle in a dispute over territorial claims to the South China Sea and risk turning the region into a "tinderbox of conflicts" after he lifted a long-standing embargo on arms sales to Vietnam.
Mr Obama's three-day visit to Vietnam was closely watched in China, which like Vietnam is a communist country, and is Vietnam's biggest trading partner. However, tensions between the two ideological allies have risen over Beijing's maritime claims to almost all of the South China Sea. Many others in the region, including Vietnam, Brunei, Taiwan, Malaysia and the Philippines, also have claims to the area.
China is building airstrips and deploying missiles on man-made islands in the Spratly archipelago, which has increased tensions with Vietnam, as well as the Philippines and Taiwan, all of which claim sovereignty. Some $5 trillion (€4.43 trillion) worth of shipping passes through the region annually.
Pivotal move "It is worrying to note the three-day visit has been described by some as a pivotal move in the US' strategic rebalancing to curb the rise of China," the China Daily newspaper said in an editorial.
The US was apparently using Vietnam to offset China’s growing influence in the region, especially since tensions were ratcheted up in the South China Sea because of competing sovereignty claims.
“This, if true, bodes ill for regional peace and stability, as it would further complicate the situation in the South China Sea, and risk turning the region into a tinderbox of conflicts,” it said.
The response from the foreign ministry to the lifting of the ban was initially positive, saying it was a “product of the Cold War and should no longer exist”, and that China was pleased to see Vietnam and the US normalising relations.
However, when Mr Obama stressed freedom of navigation in the South China Sea, and told an audience in the Vietnamese capital Hanoi that "big nations should not bully smaller ones", even without explicitly mentioning China, this prompted a sharp response from Beijing.
Foreign ministry spokeswoman Hua Chunying said a country's size did not matter.
“The key point is whether countries involved have the determination and sincerity to resolve disputes via talks and consultations,” she told a media briefing.
Human rights Mr Obama highlighted human rights issues in Vietnam during his three-day visit, in particular the fact that activists had been blocked from meeting him.
“There are still areas of significant concern in terms of freedom of speech, freedom of assembly, accountability with respect to government,” he said.
However, China's Global Times newspaper, which is published by the Communist Party's official People's Daily, accused Washington of being all too willing to soften its stance on human rights if it helped to contain China.
“Trade in arms between the US and Vietnam, two nations with completely different political systems, is of great symbolic significance,” it said in an editorial.
"Obviously, Obama is planning to create some diplomatic legacies before leaving office, as well as further promote the rebalance to the Asia-Pacific. When the US has an urgent need to contain China in the South China Sea, the standards of its so-called human rights can be relaxed," the Global Times said.
Tensions are set to ratchet up further in the coming weeks as the Permanent Court of Arbitration in The Hague rules on an arbitration case filed by the Philippines in relation to the South China Sea disputes.