Libya's cumulative losses from the current oil blockade imposed by forces allied to eastern military commander Khalifa Haftar since January have neared $5 billion, the National Oil Corporation (NOC) said in a statement on Thursday. The state-run NOC said the blockade caused an unprecedented decline in oil exports, and the country’s revenues are not enough to cover 10 per cent of the salaries. The Libyan National Army led by Field Marshal Haftar and forces aligned with the internationally recognised Government of National Accord (GNA) in Tripoli have been fighting since April last year for control of the capital. The military tide has been reversed in recent weeks, and his forces lost several towns and a key airbase. Field Marshal Haftar's side controls the country’s east and most of the south, while the GNA controls areas in the west, including Tripoli. On Saturday, he had vowed to continue fighting. In a two-minute audio speech addressed to his forces, he said they “will fight and fight” against “Turkish colonialism”. Turkey is aiding the embattled government in Tripoli. It has recently stepped up its military support with armoured drones, air defences and Syrian mercenaries with links to extremist groups. US President Donald Trump has called for a "rapid de-escalation" of the Libyan conflict on a call with Turkey's President Recep Tayyip Erdogan on Saturday.