Nigerians are concerned about not being able to reach their families in the north-western state of Zamfara after authorities shut down internet and mobile phone services.
The shutdown comes as security forces fight to contain armed gangs who have been carrying out killings and kidnappings for ransom.
The move, for an initial period of two weeks, followed a request by the Zamfara state government, an official of Nigeria’s Communications Commission told the BBC.
It came just days gunmen abducted more than 70 schoolchildren in the town of Kaya-Maradun.
The authorities believe the shutdown of communications will help security forces track down gunmen behind the rising violence in the region.
But there are also concerns that the armed gangs could move to other states where mobile phone networks are available.
The Nigerian air force and ground troops are reportedly carrying out massive operations targeting camps of the armed gangs inside forests in the area.
The kidnappers are believed to co-ordinate their activities and negotiate ransom payments for the release of their victims through mobile phones.
This is the latest measure by the authorities to deal with the crisis.
Several states in the region have already banned the weekly open-air markets and interstate transportation of livestock.
Movement of vehicles has also been restricted from dusk to dawn and all schools have been shut in the state, which is one of the worst hit by violence.