CARL AZUZ, CNN 10 ANCHOR: Hi, I'm Carl Azuz.
Thank you for taking 10 for CNN 10.
U. S. military officials are investigating a terrorist attack that happened in Northern Syria Wednesday.
U. S. Central Command says four Americans were killed.
Two were U. S. service members.
One was a civilian with the Department of Defense and one was a DOD contractor.
The attack apparently took place while U. S. troops were on a routine patrol in the city of Manbij and the terrorist group ISIS which stands for Islamic State In Iraq and Syria claimed it was responsible.
It said the assault was carried out by a suicide bomber wearing explosives.
The U. S. has about 2,000 troops serving in Syria.
Before Wednesday's attack, two American service members had been killed in action there since the current operation began in 2014.
