Oil cargoes sail from Libya despite disruptions

ATHENS/LONDON (Reuters) - Over 2 million barrels of oil have left Libya on tankers in the past 24 hours despite ongoing port disruptions and reduced production, shipping and trade sources said on Tuesday.

Libya could descend into civil war if leader Muammar Gaddafi refuses to quit, the United States said on Tuesday, its demand for his departure carrying fresh weight after news of Western military preparations.

Two fully loaded Greek tankers carrying around 1.2 million barrels of crude oil left the Libyan port of Es Sider on Tuesday, the vessels' owner said on Tuesday.

"Both of our tankers have left the port of Es Sider, fully loaded and are sailing to Italy," an official at Greece's Polembros Shipping Ltd told Reuters.

Separately, Bermuda headquartered group Teekay Tankers said one of its vessels, carrying 1 million barrels of Libyan crude had sailed from the eastern port of Marsa el Hariga on Monday.

Another one of their vessels was turned away from the eastern port of Zuetina in the past few days.

"An unsafe port was the reason given to us," Bruce Chan, Teekay Tanker's chief executive elect, told Reuters.

Chan said the group had a third tanker currently in the port of Ras Lanuf. All three tankers were suezmax vessels which can each carry a maximum of 1 million barrels.

"It has received only half a cargo, which is unusual," Chan said. "There seems to be mixed messages: some ports might still be receiving oil while others might have been cut off."

Trade and shipping sources said communications difficulties with Libya were making it hard to get complete information on port conditions, which was leading to conflicting reports.

At least two oil ports in Libya reopened to load crude oil to tankers on Tuesday after most operations had stood at a virtual standstill due to reduced production and bad weather since late last week, they said.

The sources said the Zawiyah and Mellitah ports reopened, while Zuetina remained closed due to bad weather. Es Sider and Tobruk continue to operate.

If these ports operate at normal levels, the export volumes altogether total about 900,000 to 1 million barrels per day, according to Reuters calculations.

Zuetina is likely to start loading crude oil when the weather recovers, two crude oil traders said.

"They are trying to open Zuetina but not yet," said one oil trader with a company which buys Libyan oil. "Others are open more or less."

Libya's oil output has dropped by almost half due to the departure of oil workers, while its oil installations are undamaged, the chairman of Libya's National Oil Corporation told Reuters on Tuesday.

The comments point to a consensus emerging that about 800,000 barrels per day (bpd) of output in the world's 12th-largest exporter has been shut down, not as high as some estimates of more than 1 million bpd.

(Additional reporting by Ikuko Kurahone, Zaida Espana and Jessica Donati in London; editing by Keiron Henderson)