Libya's National Oil Co (NOC) on Thursday lifted a force majeure on a crude export terminal recovered from rebel hands, opening the way for renewed exports.
The army announced Wednesday it had taken control of Al-Hariga and Zueitina ports under a deal to end a crippling nine-month blockade by rebels seeking autonomy in the country's east.
NOC said in a statement that it had "lifted the state of force majeure on Al-Hariga only from noon (1000 GMT)" on Thursday.
The port has a daily capacity of 110,000 barrels.
NOC did not say why it had not taken similar action at Zueitina, which has a capacity of 100,000 bpd.
Renewed oil exports will restore a much-needed revenue stream for the weak central government following the 2011 overthrow of Moamer Kadhafi.
The rebels' seizure of four eastern oil terminals last July in pursuit of their campaign for restored autonomy for the eastern Cyrenaica region slashed output from 1.5 million barrels per day to just 250,000 bpd.
Tripoli says the blockade has cost the country more than $14 billion (10.1 billion euros) in lost revenues.
Under the deal reached on Sunday, the rebels were to hand over the two terminals this week and cede the other two within two to four weeks, provided negotiations are successfully concluded.
The NOC declared force majeure at the four terminals in August, clearing it of liability for failure to honour contracts and bringing all oil exports to a halt.
The recovery of Ras Lanouf and Al-Sidra will be an even bigger prize, as they have a combined capacity of 550,000 bpd.
Western governments issued a joint statement Monday calling for a rapid reopening of the oil terminals.
They called for "the prompt establishment of a transparent and inclusive national dialogue that includes particular focus on the fundamental national and regional questions involving Libya's resources."
Details of Sunday's agreement have been kept under wraps.
But the rebels have been demanding a referendum on restoring the autonomy that the Cyrenaica region enjoyed for the first 12 years after Libyan independence in 1951.
They have also sought full back-pay for their men, who were employed as security guards at the oil terminals before launching their blockade.
A Western diplomat said the rebels were "trying to find a way out of the crisis they created" with an abortive oil export bid on a rogue tanker last month.
The US Navy intercepted the tanker and returned it to Libya, and the UN Security Council passed a resolution banning all unauthorised Libyan oil exports.