A $100 banknote is placed next to 100 yuan banknotes in this October 16, 2010 file picture illustration taken in Beijing. [Photo/Agencies]

China, the biggest buyer of US Treasury securities, cut its holding in December to a 10-month low, the latest data from the Treasury Department showed on Tuesday.

China reduced its holding by $18.4 billion to $1.2461 trillion in December, coinciding with the country's sharpest monthly fall in foreign reserves.

The country's forex reserves dropped to $3.33 trillion in December, the lowest levels since 2012, according to official data.

Japan, the second largest foreign holder of US Treasury securities, also cut its holding in December by $22.4 billion to $1.1225 trillion.

Net selling by foreign governments of US securities, including Treasuries, agency debt, corporate bonds and stocks, totaled $51.3 billion, marking the biggest monthly outflow on record for official holders, reported Bloomberg citing the department.

Xinhua contributed to this story.