LONDON - China surged clear at the top of the Olympic medals table on Sunday, as two world records fell in the pool on a night when France stunned swimming's superpowers to take a dramatic relay gold.

After dominating day one of competition with four gold medals, Chinese athletes hit paydirt once again with wins in shooting for Guo Wenjun and synchronised divers Wu Minxia and He Zi.

Guo successfully defended her 10m air pistol title with a thrilling last-shot finish at the Royal Artillery Barracks to overhaul France's Celine Goberville, who had led going into the last round.

Legendary diver Wu, meanwhile, clinched her third consecutive gold medal in the 3m springboard synchronised after wins in 2004 and 2008.

Day two of the swimming competition saw another thrilling night of action, where records tumbled once more before France surged to the country's first ever gold in the prestigious 4x100m freestyle relay.

The French quartet of Amaury Leveaux, Fabien Gilot, Clement Lefert and Yannick Agnel clocked 3:09.93, Agnel coming from behind on the last leg and overtaking American anchor Ryan Lochte for the triumph.

Russia took the bronze but the much-fancied Australia, who had led off with James Magnussen, trailing home in fourth.

It was sweet revenge for France, who were pipped to gold by the Americans at the 2008 Games in Beijing, losing by just 0.08sec.

"What happened four years ago, that was really tough -- this is an extraordinary revenge," Gilot said.

American Dana Vollmer won the women's 100m butterfly gold medal, clocking a world record of 55.98sec for a crushing victory over China's Lu Ying.

Vollmer became the first woman to break through the 56-second barrier as she added Olympic gold to the world title she claimed last year.

"I just relied on my strengths," Vollmer said. "Just set it up well, passed a few people and charged it home."

South Arican Cameron van der Burgh won the men's 100m breaststroke gold in a world record of 58.46sec before dedicating his win to late former training partner, Norway's Alexander Dale Oen who died from heart failure in April.

"I just have to pay tribute to Alexander Dale Oen tonight, I know he has been with me this year, I think he helped me finish the race in such a strong manner," van der Burgh said.

France's Camille Muffat won the women's 400m freestyle gold with Britain's defending champion Rebecca Adlington in third.

While China celebrated their burgeoning gold haul, hosts Great Britain were still waiting for their first win with cyclist Lizzie Armitstead settling for silver in a thrilling road race won by Marianne Vos of the Netherlands.

United States shooter Kim Rhode took the gold medal in the women's skeet, her fifth consecutive visit to the podium following medals at Atlanta, Sydney, Athens and Beijing.

Uzbek gymnast Luiza Galiulina was provisionally suspended after testing positive for the banned diuretic furosemide, the International Olympic Committee (IOC) announced.

Galiulina underwent a drugs test on July 25, three days before the start of the women's competition.

Meanwhile, St. Kitts and Nevis record sprinter Tameka Williams has been sent home from the Olympics after admitting taking a banned substance.

Williams, 22, the Caribbean country's 100m and 200m record-holder, did not fail a drugs test but made the revelation during discussions over vitamins and nutritional supplements, an official told AFP.

Spain's footballers will also be making an earlier-than-expected departure from London after crashing out of the tournament.

The world and European champions, beaten 1-0 by Japan in their opening

game, suffered a 1-0 upset defeat to Honduras in a stormy Group D match at Newcastle which saw 13 bookings.

In other action on Sunday, the United States' collection of NBA multi-millionaires, who are expected to cruise to a successful defence of the basketball title, eased past France 98-71 in their opening game.

Over at Wimbledon, Maria Sharapova, Novak Djokovic and home hope Andy

Murray were all winners on a rain-hit day. (AFP)