US-based United Airline will make its last flight from Houston to Lagos Nigeria at the end of June, effectively ending the carrier’s only route to Africa.

The airline has blamed difficulties in collecting money from ticket fares due to foreign exchange restriction by the West African nation’s central bank, and weakness in the energy sector, as the main reason it has decided to pull the route.

According to a note by the airline seen by Bloomberg, the Nigerian route has been underachieved for years but was kept alive because of its importance to Texas-based customers, United Continental Holdings Inc.

“United confirms that it will discontinue its service between Houston and Lagos. The last departure from Houston will be on June 29 and the last departure from Lagos will be on June 30,” Kevin Johnston, the Head of Press, Europe, Africa, Middle East and India for United Airlines, told PUNCH in an emailed statement.

“We have regretfully taken this decision because of the route’s poor financial performance. We will contact customers with bookings for flights beyond those dates to provide refunds. We apologize for any inconvenience caused.”

Its exit will only leave Delta Air Lines as the only US-based carrier flying to Africa.

In April, Spain’s national carrier, Iberia Plc, ended its flights to Nigeria citing a fall in passenger traffic to the oil producing nation.

Before United Airlines had officially confirmed the planned exit from the country, the company’s official twitter account responded to an individual tweet inquiring about a rumor, SaharaReport said.

The airlines spokesman, Jonathan Guerin, told Bloomberg that the repatriation of hard currency from Nigeria has been “a significant issue”, and the unavailability of aviation fuel had necessitating the closure of the route.

The International Air Transport Association (IATA) revealed that as of March the Nigeria owed airlines $575 million in air fares due to the Federal Government’s policy on foreign exchange.

Nigeria restricted the amount of money that can be moved abroad after the global slump in oil prices depleted the government’s U.S. currency reserves.