Mainland Chinese stock markets unexpectedly slumped again on Tuesday, with the primary index for the Shanghai market plunging by 6.2 percent. The stock sell-off was the steepest since an 8.5 percent decline in Shanghai on July 27, which was the market's biggest daily drop in eight years.

China’s central bank poured the largest amount of cash into the financial system on a single day in almost 19 months, signaling Beijing’s growing concerns about capital flowing out of the country following the recent weakening of its currency.

On Sunday, the U.S. government made a regrettable move by ordering the Chinese law enforcement personnel in the country for the "Fox Hunt" operation to return home immediately. Regrettable is such action as China's operation is legitimate and has been approved in bilateral agreements reached earlier this year.

The Obama administration has warned China about the use of undercover operatives in the United States who are assigned to pressure Chinese fugitives to return home and in some cases to recover assets gained through alleged corruption, U.S. officials said.

Mr. Ling is now the focus of political intrigue that could overshadow a visit to the U.S. in September by China's leader, Xi Jinping. Diplomats and analysts said Mr. Ling might have had access through this brother to sensitive information about Chinese leaders.

Employees should be given more flexibility in summer to take half-day vacations on Fridays, giving them extra time for weekend travel and boosting the tourism industry, the State Council suggested.

Financial markets have reacted to signs that Chinese authorities believe it is necessary to act to boost flagging growth, said Ewen Cameron Watt, chief investment strategist at BlackRock's Inc.'s Investment Institute.

The central bank set the official value of the renminbi nearly 2 percent weaker against the dollar. The devaluation is the largest since China's modern exchange-rate system was introduced at the start of 1994. China's abrupt devaluation is the clearest sign yet of mounting concern in Beijing that the country could fall short of its goal of roughly 7 percent economic growth this year.

China devalued the yuan on Tuesday after a run of poor economic data, guiding the currency to its lowest point in almost three years in a move it billed as free-market reform. The central bank described it as a "one-off depreciation" of nearly 2 percent, based on a new way of managing the exchange rate that better reflected market forces, but economists said the timing suggested it was also aimed at helping exporters.

Stocks in China posted their biggest one-day gain in a month after weak economic data lifted expectations Beijing would boost spending and continue to prop up the market by buying shares.