The collective wars in Afghanistan, Iraq and Syria have cost U.S. taxpayers more than $1.5 trillion since Sept. 11, 2001, according to a Defense Department report.
The current U.S. military operations, designated Operation Freedom's Sentinel in Afghanistan, Operation Inherent Resolve in Syria and Iraq, and Operation Noble Eagle for homeland security missions in the U.S. and Canada, have accounted for $185.5 billion of that sum.
Of the three current operations, Freedom Sentinel takes the lion's share of costs at $134.3 billion, followed by Noble Eagle at $27.7 billion, and Inherent Resolve at $23.5 billion. According to the report, the money goes toward training, equipment, maintenance as well as food, clothing, medical services and pay for troops.
Ahead of an announced trip to Afghanistan, Secretary of Defense James Mattis told reporters traveling with him that he was hopeful peace talks with the Taliban would signal an end to America's longest war. The fight in Afghanistan has been ongoing for the last 17 years.
"Right now, we have more indications that reconciliation is no longer just a shimmer out there, no longer just a mirage," Mattis said.
"It now has some framework, there's some open lines of communication," Mattis added.
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Over the summer, a top U.S. State Department official met Taliban officials in Qatar to try to lay the ground work for broader peace talks.
The visit is Mattis' fourth time in the country since becoming Defense secretary, and it's part of a larger trip including stops in San Diego and India.
Mattis' visit to Afghanistan comes amid recent attacks.
A U.S. service member was killed and another wounded Monday in "an apparent insider attack" in eastern Afghanistan, according to a statement from the Resolute Support, the NATO-led coalition in Afghanistan. On Wednesday, 20 people were killed in twin bomb attacks in Kabul. ISIS claimed responsibility for the attack.
Currently there are approximately 14,000 Americans in Afghanistan.
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