China's foreign currency reserves unexpectedly fell in September, official data showed on Wednesday, as the global economy was pressured by the coronavirus pandemic.

The country's foreign exchange reserves, the largest in the world, stood at $3.143 trillion, compared with $3.169 trillion tipped by a Reuters poll of analysts and $3.165 trillion in August.

The U.S. dollar index rose by nearly 2% in September, marking the first gain in five months, in part because a resurgence in COVID-19 cases in major economies weighed on investors' risk appetite.

The Chinese yuan posted its strongest quarter in July-September since the 2008 global financial crisis, gaining around 3.7% on the dollar as latest data underscored a continued recovery for the world's No. 2 economy.

Foreign inflows into Chinese stocks and bonds have also been strong, limiting capital outflows.

China held 62.64 million fine troy ounces of gold at the end of September, unchanged from August

The value of the gold reserves fell to $118.20 billion at the end of September from $122.62 billion at end-August.