Algerian special forces stormed a natural gas complex in the Sahara desert on Saturday to end a standoff with an Al Qaeda-linked terror group that left at least 23 hostages dead and killed all 32 militants involved, the Algerian government said.

A senior U.S. tells Fox News that details of the siege remain unclear. It is not known whether anyone was rescued in the final operation, but the number of hostages killed on Saturday — seven — was how many the militants had said that morning they still had. The government described the toll as provisional and some foreigners remain unaccounted for.

U.S. Defense Secretary Leon Panetta said much remains “sketchy” about what happened at the remote Ain Amenas gas field.

“We know that lives have been lost,” he said.

Read more: FOX