Official figures show that China's trade surplus shrank in September as growth in exports and imports slowed sharply.
The country's trade surplus fell to $16.88 billion in September compared with just over $20 billion in August. It was the lowest surplus in five months.
The figures come as China set the yuan's central parity rate - the middle of the currency's allowed trading band - at 6.6693 to the dollar, its strongest since a June pledge for limited currency reform.
But the data are unlikely to calm angry US and European politicians, who are demanding that China let the yuan rise more quickly against the dollar.
Some critics claim the yuan is undervalued by as much as 40%, giving Chinese exporters an unfair advantage by making their shipments artificially cheap.
Beijing vowed in June to let the yuan trade more freely against the dollar. Since then, the currency has advanced around 2% against the US currency.
China's exports rose at an annual rate of 25.1% in September to almost $145 billion, compared with an increase of 34.4% in August. Imports rose 24.1% to a record-high of $128 billion. But this growth was slower than the 35.2% growth recorded in August.
China has repeatedly rejected demands for a sharp rise in the yuan, with Premier Wen Jiabao telling European politicians last week that such a move would destroy Chinese businesses and fuel social instability by triggering job losses.
While China has said it wants to reduce its heavy reliance on exports to drive the economy, the export sector remains a massive employer in the country of 1.3 billion people.
