BEIJING -- China Unicom, the country's second-largest mobile operator, said Thursday that its net profits surged 51.8 percent year on year to 2.78 billion yuan ($453 million) in the first three quarters of 2013.

Business revenues reached 226.65 billion yuan during the period, up 18.9 percent from a year ago, according to a quarterly report filed to the Shanghai Stock Exchange by China United Network Communications Limited, a Shanghai-listed wholly owned subsidiary under China Unicom Group.

The company's earnings per share stood at 0.13 yuan, the report said.

In the January-September period, China Unicom took in 115.38 billion yuan for its mobile business, an increase of 20.3 percent year on year.

Revenue from 3G services amounted to 66.75 billion yuan, accounting for 57.9 percent of its total mobile business revenues. The percentage was substantially up from a share of 46 percent registered for the same period last year.

The company said it added 35.17 million 3G subscribers from January to September, bringing the total to 111.63 million by the end of the third quarter.