Other hostages believed held

Mu'ath al-Kaseasbeh: Jordanian pilot, 26, who was carrying out airstrikes against the militants.

John Cantlie: British photojournalist.

The Rev. Paolo Dall'Oglio: An Italian Jesuit priest.

Samir Kassab: A Lebanese national who worked as a cameraman for satellite channel Sky News Arabia.

Ishak Mokhtar: A Mauritanian reporter for Sky News Arabia.

Unidentified American woman: She was captured last year in Syria while working for aid groups. U.S. officials have asked that the woman not be identified out of fears for her safety.

Three workers for the International Committee of the Red Cross.

About seven Lebanese soldiers: Abducted during a cross-border militant raid in the Lebanese border town of Arsal.

ISIL has also released several hostages, reportedly in exchange for ransom money.

Associated Press