ALGIERS, Algeria (AP) — Algerian forces scoured the Sahara Desert on Tuesday, searching for five foreign energy workers who vanished during a chaotic four-day battle with hostage-taking Islamist militants.

One official says the men may have fled the sprawling complex during the fighting and gotten lost.

The four-day confrontation that began when al-Qaida-affiliated militants stormed the remote desert natural gas complex and took hostages early Wednesday, was punctuated by exploding cars, attacks from helicopters and a final assault by Algerian special forces.

In all, 37 hostages, including an Algerian security guard, and 29 militants were killed, but five other foreign workers remain unaccounted for.