SHANGHAI— China followed through today on its pledge to allow greater flexibility in exchange rates, but said an appreciation in its currency alone could not rebalance world growth as it urged world leaders to carry out more fundamental reforms.

By late today, the yuan was trading at about 6.8012 to the U.S. dollar in the spot market, strengthening from 6.8272 on Friday — as the central bank delivered on its weekend promise to give up the dollar peg imposed two years ago to help Chinese exporters cope with the global downturn.

For the past two years, Beijing has kept the yuan trading in a much narrower band around 6.83 to $1.

But analysts said the move was mainly aimed at countering criticism of Beijing's currency policies ahead of this weekend's summit of the Group of 20 leading economies and would not result in any significant shifts in exchange rates. The yuan is still subject to a 0.5 percent daily trading range, limiting volatility.

"The yuan will gain very soon, but definitely not much. It was more of a strategic maneuver to silence outside criticism," said Qian Qimin, a market analyst at Shenyin Wanguo Securities.

The central bank said plans to allow greater currency flexibility were in line with China's own needs and would help Beijing fight inflation, encourage manufacturers to improve efficiency and reduce the country's reliance on exports as a key driver for growth.

China's economy surged 11.9 percent in the first quarter of this year and exports jumped by nearly 50 percent over a year earlier in May, despite expectations that Europe's debt crisis would hit demand in the 27-nation European Union, China's biggest trading partner.

While foreign manufacturers have welcomed the relief a stronger yuan would bring, exporters in China, already operating on razor-thin margins, were less pleased.

China has sought to deflect criticism, noting that the causes of the global crisis lay well beyond its door.