KABUL, Nov. 4 (Xinhua) -- Afghanistan's leading cellular operator Roshan said on Saturday that it would upgrade its cooperation with its major equipment and infrastructure supplier Siemens to meet the increasing telecommunication service demand inthe war-torn country.

This announcement came just four days after the company reached one million people out of Afghanistan's 31 million population.

Roshan, with a full name as The Telecom Development Company Afghanistan, launched its service in July 2003, after getting a GSM service license in January 2003. Currently, its service covers a total of 155 cities and towns, or 39 percent of Afghan population, according to Karim Khoja, Chief Executive Officer of Roshan.

Afghanistan has been seeing a rapid increase of telecommunication service demand since Taliban's fall in 2001, as the post-war reconstruction work is picking up speed.

Currently, there is an estimated 1.5 to 2 billion dollars' worth of telecommunication service market in the country. In 2006,Afghanistan has registered a 400 to 500 million dollars annual growth for the service market, which is expected to double in coming three years, Afghan Minister of Communications Amirzai Sangin told Xinhua.

Nearly 50 percent of Roshan's network uses Siemens' network infrastructure. To date, Roshan has spent over 45 million dollars on Siemens equipment and infrastructure, said Khoja.