Department of Foreign Affairs spokesman Charles Jose said the Philippines was working with the employer of the nine, Austrian-owned VAOS Oil Service, the Libyan government and embassies of the other foreigners abducted on Friday. An Austrian, a Czech, two Bangladeshis and a Ghana national were also taken.
Austria's Foreign Ministry believes the attackers are Islamic State-allied militants from nearby Sirte, but Jose said "we can't say at this point" if they are.
"These cases underscore the escalating threat to the safety and security of Filipino oil workers in Libyan oil fields which have been targeted by armed groups in recent weeks," Jose said.
He appealed to around 4,000 Filipinos still in Libya to get in touch with the Philippine embassy and avail of the government's mandatory repatriation program which covers the cost of travel back to the Philippines.
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The Al-Ghani oil field had suspended operation for two weeks prior to the attack and most of the workers had left by the time the gunmen arrived there, he added.
The Philippines is among the world's top labour exporters with about a tenth of its 100 million people working abroad.