Other foreigner hostages were found in the Sahara during Islamist militants' seizure of hundreds of hostages in Algeria.
The official, a member of Prime Minister Abdelmalek Sellal's office, said Tuesday the missing foreigners may have tried to escape into the desert and got lost.
An al-Qaida-affiliated band of fighters attacked the vast natural gas complex Jan. 16 and 37 hostages, including an Algerian security guard, died in the four-day standoff.
Many foreigners escaped from the site during the attack and were found by the army wandering through the desert, the official said, speaking on condition of anonymity because he was not authorized to speak to the press.
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