Belgium said on Monday (September 16) it was investigating suspected foreign state espionage against its main telecoms company, which is the top carrier of voice traffic in Africa and the Middle East, and a newspaper pointed the finger at the United States.

The investigation was launched after the former state telecoms monopoly Belgacom filed an official complaint in July about the hacking of several servers and computers.

Federal prosecutors said in a statement the inquiry had shown that an intruder with significant financial and logistics means was behind the attack and that the complexity and the scale of the hacking pointed towards international state-sponsored cyber espionage.

The prosecutors declined to say which foreign state they suspected.

Although it was filed in July, the complaint was only made public on Monday.

The government of Belgium, which has a majority stake in Belgacom, condemned the intrusion and the violation of a public company.

The Belgian daily De Standaard said the NSA had been monitoring international telephone traffic through Belgacom for two years. It said the hackers had been primarily interested in Belgacom's subsidiary BICS, a wholesale provider of international phone lines and biggest voice carrier in Africa and the Middle East.

Prosecutors said the intruder had used malicious software and advanced encryption techniques with the aim of gathering strategic information, and had not sabotaged Belgacom's data or sought to cause direct economic damage.

Presented by Adam Justice