Vietnam and the United States on Monday began their annual naval exchange near a former U.S. army base in Danang city amid mounting tensions over competing sovereignty claims in the South China Sea.
With salvage and disaster training as well as a performance from the military band, the schedule of events seems harmless enough. However, some observers say the activities are an intrinsic part of a delicate diplomatic balancing act over contested territory in the South China Sea.
This year's event is larger than in 2011, with 1,400 personnel and three ships, including a guided missile destroyer, said Lieutenant Commander Mike Morley who attended the opening ceremony.
"This was coordinated about a year ago so this is a long planned event which is going to be taking place this week," Morley said.
The exchange overlaps with war games involving the United States and the Philippines that began last week. The exercises come during a naval standoff between the Philippines and China near the Scarborough Shoal in the South China Sea.
Beijing insists the entire 3.5 million-square-kilometer sea is part of its territory. The Philippines, Malaysia, Taiwan, Brunei and Vietnam also claim portions of the waterway.
The latest spat began on April 10 when two Chinese navy ships blocked the mouth of the shoal as Philippine navy personnel prepared to arrest the crews of eight Chinese fishing boats on suspicion of poaching.
But Morley insisted there is no connection between the timing of the naval exercises with Vietnam and the Philippines.
"The two are completely unrelated," he said. "There are two completely different groups organizing each event."
Beijing called the timing of last year's activities in Danang "inappropriate," but this time around China has remained mute -- about both the Vietnamese and the Philippine drills.
However, some observers say background events are also playing a part. For example, just last week Vietnam charged blogger Nguyen Van Hai -- a well-known critic of China -- for publishing anti-state propaganda.
The move is part of Vietnam?s careful diplomatic balancing act with China, said Professor Carl Thayer from the University of New South Wales. On one hand, Vietnam holds naval activities with the United States and, on the other, it continues a dialogue with China.
As part of this, said Thayer, both countries agreed to control public opinion following rare public demonstrations against China last year.
"In Vietnam?s case, they ended the demonstrations that were occurring in public and cracked down on the bloggers."
In another turn of events, on Saturday China released 21 Vietnamese fishermen who were detained on March 4 while fishing near the Paracel Islands, an archipelago controlled by China but also claimed by Vietnam.
The release was a good move by China, said Thayer.
"By doing that it helps China divide the Philippines from Vietnam. The Philippines has been the most vocal and Vietnam has profited from it because, like an athlete on a bike race, it can sail behind the Philippines and get a lift higher with forward momentum without having to lose as much energy."
Not everyone agrees these incidents are relevant to the naval activities. Dr. Ian Storey, a senior fellow at the Institute of Southeast Asia Studies in Singapore, said the release of the fishermen is part of the inevitable cycle of confrontations surrounding the South China Sea.
"Part of it is to do with the weather," Storey said. "The monsoon season is over now. When the monsoon season ends, fishing ships and survey vessels they put out to sea and these kinds of incidents start all over again."
China may have coordinated its first ever-war games with Russia to coincide with the-U.S.-Philippines drill, said Storey. China is the second largest defense spender in the world, with expenditures many times higher than all the ASEAN countries together. He said the naval exercises are intended to show China is a military power to be reckoned with.
"The military balance of power is shifting in China?s favor, and before long, China will have a range of capabilities that will enable it to bring coercive pressure on the other claimants, should it so wish to."
Analysts say that is why Vietnam moving quickly to improve military relations with its one-time adversary, the United States.
U.S. Navy officer Morley said the exercises in Vietnam have played an important part in beefing up bilateral ties, which have been improving steadily since relations were normalized in 1995. Morley said he expects the events of coming years to just keep getting bigger.