Two suicide car bombers attacked the offices of mobile phone operators India's Airtel and South Africa's MTN on Saturday in Kano, killing themselves but no civilians, police said.
Islamist sect Boko Haram has previously targeted phone firms, blowing up telephone masts and offices, saying the companies help the security forces catch its members.
"The one who hit the Airtel office was shot by military men before the bomb exploded ... at the MTN office the car rammed into the fence but no civilians were killed," Ibrahim Idris, the chief of police in Kano, told Reuters.
Airtel Nigeria's parent company Bharti Airtel, India's top cellphone operator, gave no immediate comment.
The national emergency agency confirmed the bombing and said it was not aware of any civilian casualties. The security forces have played down the death toll in previous bombings.
Unconfirmed reports say four persons are feared dead in the both suicide attacks, as it is not however clear the reason for targeting the service providers and if there are other institutions under fire as at the time of this report..