The United States on Tuesday called for an immediate resumption of Libya’s lifeline oil exports that have been blocked by forces loyal to military strongman Khalifa Haftar since last week. Haftar’s forces, at war with fighters loyal to the UN-recognized Government of National Accord, blocked oil exports from Libya’s main ports on Saturday, a day before an international peace conference.

The move to cripple the country’s main income source was a protest against Turkey’s decision to send troops to shore up Haftar’s rivals. The disruption was expected to more than halve daily crude output to 500,000 barrels from 1.3 million barrels, leading to losses of $55 million a day, the NOC warned.

The oil-rich North African country has been torn by fighting between rival armed factions since a 2011 NATO-backed uprising killed dictator Moamer Kadhafi and toppled his regime.