(Bloomberg) - Global finance chiefs persuaded China to join a foreign-exchange peace pact as they sought to contain the tensions unleashed by the country's stock-market rout and its August devaluation.

Finance ministers and central bankers from the Group of 20 (G-20) nations pledged on Saturday to "refrain from competitive devaluations" in the final communique from their two-day meeting in Ankara.

That is the first time the G-20 has used such language since 2013.

China is on the defensive as its slowing economy and market turbulence send shock waves through emerging markets just as the United States is preparing to raise interest rates.

With the MSCI emerging market index down 18 per cent so far this year, an earlier version of the statement prepared before the meeting cited "recent volatility in financial markets" and the need to monitor potential spillovers.

The Chinese delegation's presentation was the main focus of the two-day meeting, Spanish Economy Minister Luis de Guindos said.

"There's been an excess of investment and an excess of indebtedness - it will take time to clean up those excesses," Mr Guindos told reporters.

"They are heading to a new normal situation for them, which will be growth around 6 or 7 per cent."

China's surprise decision to revalue the yuan as it tried to contain the stock market turmoil caused the currency to drop the most in 21 years last month, triggering exchange-rate declines elsewhere in the emerging world on concern that a weaker yuan will hurt countries exporting to China.

'It Wasn't Enough' Zhou Xiaochuan, governor of China's central bank, told his counterparts that his country had had to deal with the bursting of a stock market bubble as he described policy makers' plans, according to Japanese Finance Minister Taro Aso.

"It wasn't enough," Aso told reporters. "They may have tried to be constructive, but they weren't detailed enough."

The Chinese delegation said they were trying to limit disruption as the economy shifts to a different growth model, according to an international official participating in the talks. They said they are trying to reduce indebtedness and planning measures that will regulate swings in the stock market.

The last time the G-20 issued such a firm statement against currency wars, Japan was in the spotlight as its campaign of monetary stimulus pushed the yen to its lowest level against the dollar in more than three years.

China allowed the yuan to drop after the Shanghai Composite index lost about 40 per cent from a three-year high in June.

"China is definitely trying to play a constructive role," Canadian Finance Minister Joe Oliver said in an interview. "It is the second-largest economy in the world and so when it slows down it has global implications. That is what I thinkwe are dealing with."

The Chinese delegation said the currency move was not an attempt to grab exports from their international competitors and that explanation was accepted by the other nations, according to the international official.

"No one can predict exactly on the market volatility, but I'm confident that the renminbi exchange rate will be more or less stable around the equilibrium level," Mr Yi Gang, China's deputy central bank governor, said in an interview as he headed into Friday's session. "The Chinese economy's fundamentals are fine."

The Chinese asked for specific references to their problems to be left out of the final communique, a euro-area aide said.

U.S. Treasury Secretary Jacob J. Lew told Chinese Finance Minister Lou Jiwei in Ankara on Friday that it's important for China to signal that it will allow market pressures to drive the yuan up as well as down. China should avoid persistent exchange- rate misalignments and refrain from competitive devaluation, Lew said, according to a Treasury statement.

Fed Hikes China's slowdown comes as the Federal Reserve is considering raising U.S. interest rates for the first time in nine years. Vice Chairman Stanley Fischer explained the arguments for and against an early increase in U.S. interest rates, de Guindos said.

The draft statement seen by Bloomberg News before the talks began said that in line with the improving outlook, "monetary policy tightening is more likely in some advanced economies, which may remain one of the main sources of uncertainty in financial markets."

Some delegates from emerging markets said at the meeting that the Fed should get on with raising rates to end uncertainty, according to an official who was present.