Wintershall, the oil and gas exploration arm of chemicals company BASF, said it was preparing to wind down oil production in Libya and fly out international staff in response to unrest.

The firm said it was making preparations to fly out some 130 people of German, Dutch, Canadian, British and other nationalities and their families to ensure their security.

In accordance with its local partner, Libya's National Oil Corporation (NOC), Wintershall is taking steps to gradually close oil production, which currently amounts up to 100,000 barrels per day, it said.

The Tripolis office of Wintershall would be temporarily unstaffed except for a small core staff.

"The return will depend on further developments in the country," it said.

Wintershall has been active since 1958 in Libya, one of Africa's biggest oil producers. It produces at inland fields as well as offshore, where French oil company Total has the lead, and is also involved in exploration in the south-eastern Kufra region.