Long-haul carrier Emirates will suspend flights to Nigeria from next month over an inability to repatriate funds from Africa’s most populous nation, the Dubai-based airline has said.

The decision announced on Thursday highlights the difficulties faced by international carriers that fly to Nigeria, which is one of the biggest markets in Africa.

The African country has restricted access to foreign currency for imports and for investors seeking to repatriate their profits due to a shortage of dollars. Nigeria gets about 90 percent of its foreign exchange from oil but is struggling to produce due to pipeline theft and years of under-investment.

The International Air Transport Association said in June that Nigeria was withholding $450m in revenue that international carriers operating in the country had earned.

Emirates said it had made no progress in efforts to initiate dialogue with the relevant authorities for their urgent intervention.

“Therefore, Emirates has taken the difficult decision to suspend all flights to and from Nigeria, effective 1 September 2022, to limit further losses and impact on our operational costs that continue to accumulate in the market,” it said in a statement.

A Federal Ministry of Aviation spokesperson in Nigeria did not immediately respond to a request for comment.

Emirates had sent a letter to the government saying it could cut flights to Lagos, Nigeria’s largest city, this month because it could not get $85m stuck in the country as of July, a figure that had been rising by $10m per month.

Emirates said it would re-evaluate its decision if the situation over the blocked funds changed in the coming days.

Affected customers would be helped to make alternative travel arrangements where possible, it added.

Amid similar foreign exchange restrictions in 2016, several airlines reduced flights and carriers Iberia and United Airlines stopped flying to Nigeria altogether. United re-launched a Nigerian service last year, but Iberia has yet to return.

In May, a number of domestic airlines suspended flights due to soaring jet fuel prices.