NEAR ADJABIYAH, Libya (Reuters) - Libya is investigating the cause of an explosion late on Tuesday on oil and condensate pipelines to the eastern port of Zueitina, the National Oil Corporation (NOC) said.
The blast occurred at 10 p.m. local time on a section of the pipeline linking Field 103, which is operated by Zueitina Oil company, to the export terminal, the state energy firm said in a statement on its website.
It quoted acting NOC Chairman Abdulkasir Shengir as saying there were no casualties and that a crisis committee had been formed to carry out an investigation.
"Yesterday evening, some people from Ajdabiyah saw a big fire. They came here and the first thing they saw was a large pool of oil and they realised the pipeline was damaged," said an engineer working for Zueitina, who declined to be named.
"The fire was further away, and they saw the other pipeline was damaged."
A Reuters reporter saw large pools of oil in the sand around the crude oil pipeline, around 20 kms (12 miles) south of the eastern town of Ajdabiyah
Oil workers were trying to repair the damage and had cut about 2 metres of the pipeline. A fire was still burning at the condensate pipeline about 5 kms away, although officials said it was smaller than before.
Ajdabiyah is some 30 kms away from Zueitina. Plumes of smoke could still be seen from the town.
"We could put the fire out, but we want it to burn out the gas so it doesn't pollute the air," the engineer said. Regarding the oil pipeline, he said: "By tomorrow, this should be solved."
The pipeline also carries crude produced by the Abu Attifel oil field, operated by the Mellitah Oil Company, a joint venture between the NOC and Italy's Eni, and by the Nakhlah oil field, operated by Germany's Wintershall.
"Initial reports show the initial explosion was on the condensate pipeline. That then had an impact on the crude pipeline, and due to the pressure it must have burst," Musbah Al-Warfalli, a Zueitina security official and a member of the crisis committee, said.
Asked if he thought the cause may have been sabotage, he said: "We don't know. Some guards found mortars nearby, but I think these are left over from the war. The more realistic version is that there were technical problems, maybe the pressure inside."
NOC officials have spoken of plans to upgrade Libyan pipelines, many of which are old and need regular maintenance.
"Maybe by tomorrow or after tomorrow the oil will flow through the pipeline again," Warfalli said. "But for the other pipeline it will take time. A large part will need to be replaced, and we want to properly investigate the cause."
Following the 2011 uprising that ousted Muammar Gaddafi, it took Libya less time than expected to return to oil output close to the pre-war level of almost 1.6 million barrels per day (bpd). But protests have disrupted operations in recent months.
On Wednesday, Deputy Oil Minister Omar Shakmak said the OPEC member's oil output was at 1.55 million barrels bpd and could reach 1.7 million bpd by mid-2013.
(Additional reporting by Ali Shuaib in Tripoli; Writing by Marie-Louise Gumuchian; Editing by Jane Baird)