ALGIERS, Algeria – The death toll from the terrorist siege at a natural gas plant in the Sahara climbed past 80 on Sunday as Algerian forces searching the refinery for explosives found dozens more bodies, many so badly disfigured it was unclear whether they were hostages or militants, a security official said.

Algerian special forces stormed the plant on Saturday to end the four-day siege, moving in to thwart what government officials said was a plot by the Islamic extremists to blow up the complex and kill all their captives with mines sown throughout the site.

In a statement, the Masked Brigade, the group that claimed to have masterminded the takeover, warned of more such attacks against any country backing France's military intervention in neighboring Mali, where the French are trying to stop an advance by Islamic extremists.