Islamic militants have fired rockets from speedboats at Libya's largest port in an attempt to seize control of the fiercely contested resource amid warnings the country is descending into chaos like that in Syria.

Last night a rocket set three storage tanks ablaze at the eastern Libyan oil port of Al-Sidra as armed factions allied to competing governments fought over control of the country's biggest export terminal.

Rebels from a group called Libya Dawn, which helped to topple Muammar Gaddafi in 2011, seized control of the capital Tripoli in August - exiling the internationally recognised government east.

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The massive storage tank at the exporting port of Al-Sidra burns after it was struck by rocket fire

Only one tank was struck by rockets, but the intense fire led to two other tanks (pictured) bursting into flames

Firefighters stand by as the flames continue to rage. The tank was struck after militants tried to seize control of the port in a speedboat attack

Firefighters try to contain parts of the fire after the intense blaze spread to two other storage tanks

The group, which is responsible for the attack which left the tanks ablaze, are now engaged in a bitter power struggle with the incumbent government fought primarily over the country's resources.

Ali Hassi, spokesman for a security service allied to the country's east-based internationally-recognised government, said the rival force tried taking the Al-Sidra with speedboats, opening fire on an oil tank.

Ismail al-Shukri, a spokesman for the rival force, said it had launched a new push to take the ports but denied it had sent boats or shot at any storage tanks. He blamed the other side, saying aircraft had attacked the tank.

'A tank was hit but the damage is limited,' Hassi said, adding that the advance had been stopped with aircraft and ground troops.

Clashes were also reported from Sirte, a city west of Al-Sidra, killing up to 19, among them 14 guards at a power plant, residents said.

Meanwhile Libya, torn by the growing political divide that threatens to engulf its oilfields, could become the next Syria if it does not patch its divided government and get help battling Islamic militants, the country's foreign minister said this week.

A Libyan soldier looks at the body bag of a fellow soldier killed during clashes with militant forces in Benghazi

Doctors, nurses and other emergency services personnel tend to an injured Libyan soldier

'If we don't do the right thing now, in two years' time we could have - hopefully not - a repeat of what happened in Syria in 2014 because the international community didn't react adequately,' Foreign Minister Mohamed Dayri said.

In an ominous turn of events, a force allied to the self-declared Libya Dawn government earlier this month moved to seize Libya's two biggest oil export ports, Al-Sidra and Ras Lanuf. Fighting has since spread to a third oil port.

Dayri repeated his government's charge that forces attacking the oil facilities included elements of Ansar al-Sharia - a group the U.S. has designated as terrorists suspected of being involved in the deadly September 2012 attack on the U.S. diplomatic compound in Benghazi.

The fighting has reduced Libya's crude output to 352,000 barrels a day, a spokesman for state National Oil Corp said, adding that only the Brega, Sarir, Messla and offshore operations were still producing.

Al-Sidra and Ras Lanuf ports - now closed due to the conflict - had previously been processing an estimated 300,000 barrels per day.