Three Americans — two U.S. soldiers and one civilian interpreter — were killed in an ambush by an Islamic State gunman while serving in Syria. Three other service members were injured. The attack took place in Palmyra, during a joint patrol and key leader engagement operation with Syrian forces.

These were Americans who stepped up to serve in one of the world’s most dangerous regions. Their lives were cut short by an act of terrorism — carried out by a lone gunman who was engaged and killed, but whose attack raises critical questions about operational safety and the ongoing threat from ISIS.

Now, we call on the U.S. government and international partners to deliver full justice and accountability for this attack — not only in words, but in clear action.

We demand:

• A full public investigation into the circumstances surrounding the ambush
• Immediate support for the families of the fallen, including recognition of the interpreter’s sacrifice
• A coordinated international response to dismantle remaining ISIS cells in Syria and Iraq
• Greater transparency from U.S. officials on the scope and strategy of U.S. operations in Syria.

The fallen deserve to be remembered — and their killers must not escape consequences. As the Defense Secretary stated, “If you target Americans, we will hunt you down.” That must not be an empty promise.

Add your name to demand justice for the Americans killed in Syria and a full, lasting response to this act of terrorism.