The nine foreign hostages include 4 Filipinos, 2 Europeans, one Ghanian and one or more Bangladeshi. Another independent report said the nationals from Europe were Czech and Austrian.
The attack was carried out Friday at the al-Ghani oil field which is south if Sirte, said officials. The gunmen are said to have killed 11 guards by beheading or shooting them, prior to being driven off.
A spokesperson from the state oil company of Libya said that foreigners from an oil services company in Austria operating at the field were still missing since the time the attack had taken place.
Militants in March also attacked and damaged a number of other oil fields in Libya close to al-Ghani, forcing the Libyan government to pull workers out and shut down the production on 11 of the oil fields.
According to one daily, a foreign ministry spokesman from the Philippines did not confirm a connection between the Islamic State and the kidnappers. During a press conference, that spokesman said in view of a worsening situation, we are appealing again to the more 4,000 Filipinos who remain in Libya to reach out to the embassy in Tripoli.
Foreigners increasingly are becoming targets in Libya, were two governments are fighting for control and the Islamist extremists have used the chaos to grow following the ouster of Moammar Gadhafi four years ago.
Countries including Britain, France, Italy, Germany, Japan, the Netherlands and the United States have shuttered their embassies.
Governments from the West are backing negotiations by the United Nations to end the Libya crisis worried that the large state in North Africa just across from them on the Mediterranean is becoming a safe haven for extremist Islamists militants.
Talks backed by the UN to form a new unity government and a cease fire that is lasting in Libya continue in Morocco. However, both sides are facing internal split over these negotiations and the fighting between two governments continues.