Nigeria's telecoms regulator has said a Sh530 billion ($5.2 billion) fine imposed on South Africa's MTN remains valid until talks with the company are concluded.
Africa's biggest mobile phone operator was handed the penalty for failing to deactivate 5.1 million unregistered SIM cards in breach of a Nigeria Communications Commission (NCC) order.
MTN said on Monday — the initial deadline for payment — that it had won a respite on the payment until the outcome of talks.
The NCC confirmed the deadline extension and that MTN had admitted the breach in a letter and "pleaded for leniency".
"The Commission has acknowledged this and is looking into their plea without any prejudice to the fine," it added.
"The fine remains but the appeal and other engagements with MTN may affect the payment deadline."
Registration of subcribers
The fine on MTN Nigeria was imposed "in the interest of the public which has been at the receiving end of security challenges", the NCC added.
"National interest is paramount because when lives are lost they cannot be replaced," the regulator said in its first formal statement on the issue.
At least 17,000 people have been killed since 2009 and 2.6 million forced from them homes in Boko Haram violence that has increasingly hit Nigeria's neighbours Cameroon, Chad and Niger.
The NCC said registration of subscribers was made mandatory to ensure proper identification of users with their biometric data and in line with international best practice.
All operators in Nigeria were involved in drawing up the regulations in 2011, it added.
The heavy fine sent MTN's share price plummeting on the Johannesburg Stock Exchange and prompted the resignation of chief executive Sifiso Dabengwa.
Dabengwa's role has been taken by acting executive chairman Phuthuma Nhleko for six months. He is involved in the negotiations with the NCC.