Libyan rebels, who seized oil ports in the country’s eastern region, say they have loaded oil on to a North Korean-flagged tanker.
The Morning Glory docked at Sidra port earlier on Saturday, after a failed attempt to dock on Tuesday.
“We started exporting oil. This is our first shipment,” a rebel spokesman said.
The rebels demand more autonomy – and oil wealth – for Libya’s east.
Analysts have said it is unlikely the ship is owned or controlled by Pyongyang.
Libya’s state-owned National Oil Corp (NOC) had warned tankers against approaching the port, and two others in Libya’s volatile east that are also controlled by armed groups.
It is not the first attempt to ship oil from the rebel-controlled port.
Rebels who seized oil ports in eastern Libya say they have loaded oil on to a North Korean-flagged tanker
On Monday, the Libyan navy ship Ibn Auf fired warning shots at a Maltese-flagged oil tanker to prevent it from docking and loading oil.
The owners of the ship complained it was fired on in international waters.
Libya’s government has tried to end a wave of protests at oil fields and ports, which have slashed vital oil revenues, but there has been little progress in indirect talks between the government and former militia leader Ibrahim Jathran, now leading the protests.
His men seized three eastern ports last year, which previously accounted for 600,000 barrels of oil a day.
Libya is struggling with armed groups and tribesmen who helped topple Muammar Gaddafi in 2011 but who have kept their weapons.
Ibrahim Jathran’s demands include an independent commission representing the three regions of Libya. He wants the commission to supervise the sale of oil and ensure the east gets a fair share of the revenue.
The government has so far not acted on threats to retake Sidra, or other rebel-controlled ports.
Libya’s oil output has slowed to a trickle since the protests started in July last year, depriving the OPEC producer of its main budget source.
President Barack Obama has said the alleged use of chemical weapons in Syria in an attack on Wednesday is a “big event of grave concern”.
Barack Obama said the US was still seeking confirmation such weapons were used, but if proved true the situation would “require America’s attention”.
Meanwhile, Syria’s main ally Russia has said there is growing evidence that rebels were behind the attack.
The opposition says hundreds died in a government assault outside Damascus.
But despite calls from many different countries, there is no sign yet that the Syrian authorities will allow a UN inspection team to visit to investigate the claims.
Unverified footage shows civilians – many of them children – dead or suffering from what appear to be horrific symptoms as a result of Wednesday’s attack.
Also on Friday, UN agencies said the number of children forced to flee Syria had reached one million.
The UN’s refugee agency, UNHCR, and children’s fund, Unicef, described the figure as “a shameful milestone”, and said a further two million children were displaced within the country.
Last year, President Barack Obama said the use of chemical weapons in Syria would cross a “red line” and force a tough US response.
Meanwhile, Russia joined calls for an “objective investigation” by UN chemical weapons experts.
Foreign Ministry spokesman Aleksandr Lukashevich said Moscow had urged President Bashar al-Assad to co-operate with a probe, but also that questions remained about the willingness of the opposition to provide “secure, safe access of the [UN] mission to the location of the incident”.
“More new evidence is starting to emerge that this criminal act was clearly provocative,” the ministry added.
President Barack Obama said the US was seeking confirmation if chemical weapons were used in Damascus attacks
“On the internet, in particular, reports are circulating that news of the incident carrying accusations against government troops was published several hours before the so-called attack. So, this was a pre-planned action.”
The ministry also described as “unacceptable” calls from various European capitals for the UN Security Council to authorize the use of force in Syria.
Other leaders have also pushed for an urgent UN inquiry.
A spokesman for UN Secretary General Ban Ki-Moon said he was “giving his utmost attention to the tragic situation” and intended to conduct a “thorough, impartial and prompt investigation”.
The UN High Representative for Disarmament Affairs, Angela Kane, will travel to Damascus on Saturday to push for access for the UN inspectors.
“It is of paramount importance that all those who share the concern and urgency of investigating these allegations, equally share the responsibility of co-operating in generating a safe environment for the [UN] mission to do its job,” Ban Ki-Moon’s spokesman added.
Damascus has described the allegations that it sanctioned the use of chemical weapons as “illogical and fabricated”.
The main opposition alliance, the National Coalition, has meanwhile said that it will do everything to assist the UN inspectors and ensure their safety.
“It is critical that those inspectors get there within 48 hours. The clock is ticking and we want to see those inspectors and we believe that the evidence will show who used those chemical weapons against innocent civilians,” spokesman Khaled Saleh told the Reuters news agency.
Opposition activists are also reportedly trying to smuggle tissue samples from victims’ bodies to the UN inspectors to prove their claims.
“The UN team spoke with us and since then we prepared samples of hair, skin and blood and smuggled them back into Damascus with trusted couriers,” activist Abu Nidal told Reuters.
Syria may have used chemical weapons against rebels, the White House has said.
US intelligence agencies believe “with varying degrees of confidence” that the nerve agent sarin had been deployed on a “small scale”, and did not say where or when it had been used.
The White House has warned chemical weapons use would be a “red line” for possible intervention, but says this intelligence does not represent proof.
Republicans in Congress called on Thursday for a strong US response.
The assessment was made in letters to lawmakers on Thursday signed by Miguel Rodriguez, White House director of the office of legislative affairs.
“Our intelligence community does assess, with varying degrees of confidence, that the Syrian regime has used chemical weapons on a small scale in Syria, specifically, the chemical agent sarin,” one of the letters said.
But it added: “Given the stakes involved, and what we have learned from our own recent experiences, intelligence assessments alone are not sufficient – only credible and corroborated facts that provide us with some degree of certainty will guide our decision-making.”
The phrase “varying degrees of confidence” is normally used to reflect differences in opinion within the intelligence community.
Syria may have used chemical weapons against rebels, the White House has said
Speaking to reporters in Abu Dhabi on Thursday, US Defence Secretary Chuck Hagel told reporters in Abu Dhabi that the use of sarin “violates every convention of warfare”.
Secretary of State John Kerry said there had been two instances of chemical weapons use in Syria.
The UK Foreign Office echoed the US claims, saying it had “limited but persuasive information from various sources” of chemical weapons use in Syria.
It is understood that Britain obtained samples from inside Syria that have been tested by the Defence Science and Technology Laboratory at Porton Down, Wiltshire.
“Material from inside Syria tested positive for sarin,” a Foreign Office spokesman said.
Syria is believed to possess large quantities of chemical weapons and there has been heightened concern among the international community in recent months about the safety of the stockpiles.
Although there have been numerous accusations, there has so far not been any confirmation that chemical weapons have been used during Syria’s two-year-old conflict.
President Barack Obama warned in December that Syrian President Bashar al-Assad would face “consequences” if he used such weapons.
The letters released on Thursday were sent to powerful US senators John McCain and Carl Levin.
In response, Senator John McCain told reporters: “It’s pretty obvious that red line has been crossed.”
John McCain recommended arming the opposition, a step the White House has been reluctant to take. He also urged taking steps to ensure that Syria’s chemical weapons did not fall into the wrong hands.
“It does not mean boots on the ground,” the Arizona senator added.
Democrat Dianne Feinstein, chair of the Senate Intelligence Committee, called for international action to help secure Syria’s stockpile of chemical arms.
Robert Menendez, the Democratic Chairman of the Senate Foreign Relations Committee, said options included “an internationally recognized no-fly zone, providing lethal assistance to vetted opposition forces, and sanctioning the transfer of arms to the regime”.
White House officials said the US would consult with allies and seek more evidence to confirm their intelligence.
On Tuesday, a senior Israeli military official accused Syrian forces of having used the nerve agent sarin against rebels several times. People can normally recover from small doses.
Speaking at a security conference in Jerusalem, Brigadier General Itai Brun cited photographs of victims foaming at the mouth and with constricted pupils and other unspecified symptoms.
Syria’s government and rebels have accused each other of using chemical weapons. A UN team is trying to enter Syria to investigate.
Sarin is a colorless and highly toxic nerve agent that can cause convulsions, paralysis and death within minutes if it is absorbed through inhalation, ingestion, or contact with skin or eyes.
According to the UN, at least 70,000 people have been killed in the Syrian conflict.