An American service member was shot and killed Tuesday by "direct fire" from Islamic State militants who stormed through defenses set up by Kurdish Peshmerga troops in northern Iraq, the U.S.-led coalition and Defense Secretary Ash Carter said.
The unnamed service member was advising Peshmerga forces in the region but was less than 2 miles behind the front lines, Pentagon Press Secretary Peter Cook said in a statement. A defense official told Fox News the service member was killed by small arms fire, likely from an AK-47 rifle.
"It is a combat death, of course. And a very sad loss," Carter told reporters in Stuttgart, Germany, where he was attending a ceremony installing a new commander of U.S. European Command. "It shows you the serious fight that we
have to wage in Iraq."
U.S. officials said the death occurred in the town of Tel Askuf, about 20 miles north of ISIS' Iraqi hub of Mosul.
A defense official told Fox News the American was killed by "direct fire" after ISIS forces penetrated the Peshmerga's forward line. Despite a push from the Obama administration to accelerate the fight against ISIS, senior defense officials say they do not believe Mosul will fall this year. 
Three U.S. military personnel have been killed in Iraq as part of the ground fight against the ISIS terror group. The last American death happened in March, when U.S. Marine Staff Sgt. Louis Cardin was killed in a rocket attack on a firebase in northern Iraq.
This past October, Delta Force Master Sgt. Josh Wheeler was killed during a rescue mission that freed as many as 70 ISIS hostages.
The latest death came following the deployment of a 200-person special operations task force to Irbil, southeast of Mosul, which Carter first announced in December. Last week, President Obama approved the deployment of 450 additional U.S. troops to Iraq and Syria.
Vice President Joe Biden visited Baghdad last week to exhort leaders of the government in Iraq to resolve internal political strife and concentrate on the effort to defeat ISIS.
Carter, likewise, visited Baghdad recently. The Obama administration has been pressing the effort against ISIS, which has been slowed down in its quest to overrun Iraq.
There are now roughly 5,000 U.S. troops on the ground in Iraq.