The official said those escaping included Americans and Europeans. He did not give any further details.
Militants attacked the Ain Amenas gas complex 800 miles (1,300 kilometers) south of Algiers on Wednesday, taking dozens of foreign workers hostage. Those being held included Japanese, Britons, French, Americans, Malaysians and Norwegians, among others.
The official spoke on condition of anonymity because he was not authorized to speak to the press.