Nigeria will enforce a Dec. 31 deadline for MTN Group Ltd. to pay a $3.9 billion fine even after Africa’s biggest wireless operator said it would challenge the penalty in a Lagos court, according to a spokesman for the communications ministry.

“MTN has the right to seek the court’s interpretation if it feels unsatisfied with the action of the regulator but nothing would stop the government action on the fine,” Victor Oluwadamilare, the spokesman for Communications Minister Adebayo Shittu, said in an e-mailed response to questions on Tuesday. Nigeria won’t consider an extension to the deadline, he said.

MTN said Dec. 17 it will ask the court to rule on the fine, saying that the penalty wasn’t within the powers of the country’s telecommunications regulator to impose. The Johannesburg-based company’s shares have declined 26 percent since the fine was made public almost two months ago. They gained 4.5 percent to 141.16 rand by the close in the city, valuing the company at 261 billion rand ($17.1 billion).

The Nigerian communications regulator imposed the penalty on MTN for failing to meet a deadline to disconnect 5.1 million unregistered subscribers as security agencies seek to fight crime in a country with poor identity records. The initial fine of $5.2 billion was reduced by 25 percent earlier this month following talks with the regulator led by MTN Chairman Phuthuma Nhleko. MTN has said it continues to engage with the Nigerian authorities even as it seeks a resolution in court.

Oluwadamilare declined to comment on what will happen if MTN misses the deadline, although Lagos-based newspaper Vanguard cited Communications Minister Shittu as saying another fine could be imposed. MTN spokesman Chris Maroleng didn’t immediately return a phone call or text message seeking comment. (Bloomberg)

•Photo shows Communications Minister Adebayo Shittu.

Update news