Chinese holdings of middle- and long-term US government bonds increased by $81.1 billion in 2013, the fastest growth pace in five years, despite the rising yields of the benchmark notes, data from the US Treasury Department showed.

Since 2009, China, the largest foreign US creditor, has increased its middle- and long-term US debt by $281.9 billion, which has provided a stable financing source for the US government.

Last year, the country's total holdings of the US debt rose by 4 percent, the second annual gain after falling in 2011 for the first time on record, according to the US Treasury.