LAGOS, NIGERIA - Nigeria's regulatory agency says former U.S. Attorney General Eric Holder is leading negotiations for South Africa-based telecommunications giant MTN about a $3.9 billion fine.

Spokesman Tony Ojobo of the Nigerian Communications Commission said Thursday Holder “is leading MTN's legal team” challenging the fine.

Former US Attorney General Eric Holder Negotiating MTN Fine

The commission fined MTN Nigeria for failing to deactivate 5.2 million unregistered cellphone SIM cards by an August deadline, saying it is a national security threat in a country where cellphones are used in kidnappings and extremist attacks.

Former US Attorney General Eric Holder Negotiating MTN Fine

MTN is challenging the fine in the Federal High Court, which has given it until March 18 to negotiate an out-of-court settlement.

Former US Attorney General Eric Holder Negotiating MTN Fine

Holder was in President Barack Obama's Cabinet from 2009 to 2015, when he returned to the Washington law firm Covington & Burling.