United Airlines said in a note to employees on Wednesday that the daily route from Houston to Lagos had underachieved for years but was kept alive because of its importance to Texas-based customers.

The last flight will be on June 30, 2016, after which Delta Air Lines will be the only major US carrier flying to Africa.

The Central Bank of Nigeria’s foreign exchange policy has restricted the movement of foreign currencies abroad after the global slump in oil prices depleted the country’s foreign reserves.

Highlighting the reason for the US carrier’s exit from Nigeria, United Airlines’ spokesman, Jonathan Guerin, told Bloomberg, “Repatriation has been a significant issue, as has been the downturn in the energy sector.”

In an emailed statement to Punch, the Head of Press, Europe, Africa, Middle East and India, United Airlines, Mr. Kevin Johnston, said, “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."

United States carrier, United Airlines, will stop flying to Nigeria next month, ending operations on its only African route because of weakness in the energy sector and difficulties in repatriating money from tickets sold in the country.

This came barely six weeks after Spain’s national carrier, Iberia, stopped flights to Nigeria, citing dwindling passenger traffic as the reason.