Niger has deactivated a third of its mobile phone connections to curb anonymous phone calls used for criminal activity, the country's telecoms regulator has announced.
"From today, non-registered SIM cards can no longer be used," said Almoustapha Boubacar, director-general of the regulator on Tuesday.
Unattributed phone numbers represented 1.7 million of the west African country's 5.4 million mobile subscribers, Boubacar said at a press conference, appearing alongside bosses from four of Niger's telecoms providers.
Niger's authorities demanded in 2012 that subscribers register with their provider in order to safeguard the security of citizens and the state "against increasing levels of criminal behaviour."
Mobile phone users were forced to show identity papers to operators during a subsequent security drive, which ended last Sunday.
Sales of previously activated SIM cards were now banned, Boubacar said.
Niger plays the unwilling host to a number of terrorist groups from Mali and Nigeria due to poor border security.
After the kidnapping of two French nationals in 2011 in the Nigerien capital of Niamey, who were ultimately killed during a rescue operation by French forces, investigators were able to trace a path using mobile phones and SIM cards from Niger to Mali via Nigeria, according to a police source.
The phone number of a "Nigerian intermediary" between Islamist terror groups Boko Haram and Al-Qaeda in the Islamic Maghreb (AQIM) had been discovered as a result, the source said.
Explore further: New patent can multiply mobile devices' uploading speed by tenfold