WASHINGTON (AP) — The White House says it will work with the Algerian government to understand how events unfolded in the terrorist attack on a natural gas complex in the Sahara desert.

Islamist militants took dozens of foreign workers hostage in a siege that ended Saturday when Algerian forces stormed the facility. The Algerian government says all 32 militants were killed and that the number of hostages killed stands at 23. One American is known dead.

An adviser to President Barack Obama says the attack is a reminder of the threat from terrorists who "will use civilians to try and advance their twisted and sick agenda."

Obama aide David Plouffe says U.S. officials will work with the Algerian government to get a "full understanding" of what happened.

Plouffe spoke on CBS and Fox.