ZHANJIANG, China (AFP) - US and Chinese sailors faced off on Chinese soil Tuesday, in sporting clashes between their navies aimed at building trust despite rising tensions over Beijing's territorial claims in the South China Sea.
The contests - the hosts claimed a 3-1 victory at football, and the visitors dominated on the basketball court - were followed by a party on board the USS Blue Ridge, the flagship of the US Navy's 7th Fleet as it paid a rare visit to the base of China's South Sea Fleet.
The fleet's frigates are charged with defending Beijing's claim to almost all the South China Sea, against several South-east Asian neighbours including allies of Washington - but the scene at the People's Liberation Army vessels in Zhanjiang was all smiles.
US 7th fleet commander Robert Thomas clinked glasses with his South China Sea fleet counterpart Shen Jinlong.
"I remembered I owed him a beer," Thomas said, before toasting a Chinese rear-admiral and cutting a cake decorated with the flags of both countries.
Chinese officers toured the hulking command ship, docked in the southern province of Guangdong, and eyed up their US counterparts over a lunch of tomato bisque and chicken paninis.
On the Blue Ridge's main deck, US personnel patrolled with M-16 rifles a stones' throw from the palm-fringed Chinese shore, while on land staff from both navies swapped jokes and rebounds.
The Chinese and US militaries - the world's largest and most powerful respectively - have been increasing exchanges even as Beijing's assertion of its South China Sea claims, most recently through rapid building of artificial islands, raises alarm bells in Washington.
Those concerns - and the M-16s - were shunted aside in public on Tuesday evening, as uniformed staff from both navies danced while a military band shook the Blue Ridge with covers of Daft Punk and hip-hop legends the Beastie Boys.
"We share the domain, we operate together," the 7th fleet's Ron Oswald told AFP when asked about South China Sea tensions.
But the smiles were belied by more serious remarks from US Admiral Harry Harris, commander of the US Pacific Fleet of which the 7th Fleet is a part, on Tuesday during a conference in the Indonesian capital Jakarta.
"China is responsible for the rise of tensions and provocations in the South China Sea," he said.
"I don't think that there's a likelihood of a major force-on-force conflict in the South China Sea today," he added. "But I have to be ready for that."
The Sea is a vital strategic waterway and close encounters between the two powers' ships have led to fears of a clash.
In their most serious maritime incident for years, a US guided missile warship, the Cowpens, had to make a sharp turn to avoid colliding with a Chinese naval ship that cut in front of it in the South China Sea in 2013, according to the Pentagon.
The two navies "interact, often daily," the 7th Fleet's Lieutenant Charles Banks said, adding that naval officials on both sides would discuss the implementation of a "Code for Unplanned Encounters at Sea" during the five-day visit.
"Ambiguity can lead to confusion and mistakes," he said, watching as US soldiers in black vests and day-glo trainers teamed up for basketball with Chinese sailors.
Terrence Phillips, a boatswain's mate on the Blue Ridge and a centre on the basketball court, said: "It's to build good relations... sport is about international camaraderie for everybody."
A female Chinese Navy engineer, who said she was not authorised to give her name, ran to take photos with Phillips, commented: "When we play basketball it's very friendly."
The US Navy eclipses China's fleet in terms of firepower - Washington has 10 aircraft carriers currently in service to Beijing's one.
But China has had double-digit military budget growth and President Xi Jinping vows to build a "strong navy" capable of "fighting and winning battles".
The base in Zhanjiang was lined with posters repeating Xi's call.
"The South China Sea has become a greater source of tension in the US-China relationship," said M. Taylor Fravel, a professor at the Massachusetts Institute of Technology, who dated the rise in friction to 2010.
At the same time, the two sides have stepped up military exchanges, with China last year joining the Rim of the Pacific exercise (RIMPAC), a major US-hosted naval drill, for the first time.
"The fact that these exchanges are occurring faster and more broadly than before underscores that the US-China relationship has both elements of cooperation and competition," Fravel added.
Despite the merriment on board, there some remarks suggested suspicion and rivalry.
"They're looking at you, be sure to wave," a US embassy staffer joked of Chinese surveillance while aboard the Blue Ridge.
One Chinese soldier took a pause from bantering with US counterparts over barbecued meat on skewers to tell a colleague: "When China entertains, its about being a good host. But the US entertains in order to display what they have."