Deutsche Telekom on Thursday confirmed its full-year profit targets after rising mobile subscriber numbers in the United States and the expansion of its fibre-optic network in Germany buoyed business in the third quarter.

"Deutsche Telekom's performance in the third quarter of 2015 was dominated by double-digit growth rates in the most important financial indicators," the company said in a statement.

Net profit increased by 59.9 percent to 809 million euros ($879 million) in the period from July to September.

Underlying profit grew by 12.9 percent to 5.2 billion euros on a 9.3-percent increase in revenues to 17.1 billion euros.

"We are resolutely forging ahead with our strategy," said chief executive Tim Hoettges.

"High investments in broadband roll-out and connectivity remain the basis for growth."

On the basis of its third-quarter performance, Deutsche Telekom said it was sticking to its goal for underlying profit to reach around 18.3 billion euros in the whole of 2015, compared with 17.6 billion euros in 2014.