LAGOS, Nigeria -- Nigeria's leading cellphone provider said Sunday it urgently needs diesel to prevent shutting down services countrywide -- the latest business hit by a months-long fuel crisis in Africa's biggest oil producer.

Many aircraft have been grounded with foreign airlines diverting to other African countries to fuel for flights abroad.

On Saturday night, some radio stations went silent.

Nigeria's woefully erratic electricity supply keeps businesses dependent on diesel generators. Nigeria produces more than 2 billion barrels of petroleum a day but imports almost all refined fuel because its refineries are not maintained.

MTN Nigeria, which has 50 million-plus customers, posted a message on Twitter overnight saying service will start deteriorating in 24 hours if it does not find diesel. Some customers already are experiencing problems and Nigeria's landline network collapsed years ago.

"MTN's available reserves are running low and the company must source for a significant quantity of diesel in the very near future to prevent a shut-down of services across Nigeria," corporate services executive Akindale Goodwill tweeted.

The crisis began when oil suppliers, hit by tightened credit lines and unpaid interest, said the government owes them as much as $1 billion for fuel and subsidies going back to October 2014. They said they could no longer afford to supply fuel without being paid.

Oil tanker drivers unpaid by the suppliers started striking last week and were joined Thursday by other oil workers.

The government, reeling from halved international prices for petroleum that provides more than 80 per cent of its revenue, is so cash-strapped it is borrowing to pay salaries, the finance minister said earlier this month.

Minister Ngozi Okonjo-Iweala denied the debt on Friday, telling journalists the suppliers are asking the government to pay their foreign exchange differential losses caused by the naira's slump from about 160 to the dollar in December to today's 218.

She accused oil suppliers of holding Nigerians to ransom and said she has asked the Central Bank of Nigeria to verify the figures because "there has been so much fraud allegations and scams in this business of oil marketing."