China's central bank says its foreign reserves, already the world's biggest, soared to $2.8 trillion at the end of 2010.

Tuesday's announcement came as Beijing faces demands by Washington and others to ease currency controls that have swelled its reserves.

The reserves rose $199 billion during the final quarter of the year and were up 18 percent over a year earlier.

The reserves have soared as Beijing controls the exchange rate of its yuan by buying up money that flows into China. Washington and others complain that keeps the yuan undervalued, giving Chinese exporters an unfair price advantage and hurting foreign competitors.