Security concerns worsen for oil firms in Libya

Expatriate oil workers in Libya are concerned about precarious security with a government struggling to impose its authority on a myriad of armed groups who refuse to lay down their weapons. The assault on the U.S. consulate and a safe house in the eastern city, in which the U.S. ambassador and three other Americans were killed, has heightened fears.

Many foreign oil firms operating in Africa's third biggest oil producer have since beefed up security measures in cities bristling with weapons and have restricted staff movements to the bare minimum.

Libya, with Africa's largest oil reserves, needs foreign investment and expertise to increase oil and gas production. Oil fields have separate, secure residential compounds and thousands of former rebel fighters guard installations.

The country is aiming to be producing 2 million barrels per day by end-2015 but delays in returning foreigners workers - specifically those working for oil services firms out in the desert fields - could derail reaching the production target.

Major oil companies operating in Libya include Italy's ENI, Germany's Wintershall, France's Total, Spain's Repsol and U.S. firms Marathon and ConocoPhillips.