In another bloody weekend in Afghanistan, four American soldiers lost their lives when an Afghan police officer turned his gun on U.S. troops in Zabul. Later that day, an Afghan soldier opened fire on a vehicle he believed was carrying NATO soldiers. One foreign civilian was wounded in that attack, the Associated Press reports.
This is hardly the first time an Afghan ally has gone turncoat.
CNN's Anna Coren met with an Afghan man who claims to have killed two of his American trainers in Wardak province in October 2009. His face covered in a shawl to remain anonymous, the 30-year-old man explained how he waited for the right moment and decided to attack when the American troops had entered a school and taken off their body armor to rest.
Explaining his decision to turn on his trainers, the Afghan told CNN that the Americans were "oppressing people" in Afghanistan. "They were burning copies of the Holy Quran and disrespecting it," the alleged attacker added.
The growing number of "insider attacks" has sparked concern among American lawmakers and raised fears that the assaults may pose significant challenges to the Obama administration's exit strategy in Afghanistan.
This weekend's assaults drew strong condemnation from Army Gen. Martin Dempsey, the U.S.'s top commander. Dempsey called the green-on-blue attacks "a very serious threat" to the war effort, according to the Associated Press. U.S. Defense Secretary Leon Panetta described the assaults as a "last gasp" of a Taliban insurgency, the AP added.
Watch Coren's report in the video above or on CNN's website.
Start of War: Oct. 7, 2001
<em>American soldiers hide behind a barricade during an explosion, prior to fighting with Taliban forces November 26, 2001 at the fortress near Mazar-e-Sharif, northern Afghanistan. (Photo by Oleg Nikishin/Getty Images)</em>
Number of U.S. Troops in Afghanistan: 88,000
<em>US Marines with the 26th Marine Expeditionary Unit deployed from the USS Bataan's Amphibious Ready Group arrive December 14, 2001 at an undisclosed location with field gear and weapons. (Photo by Johnny Bivera/Getty Images)</em>
Number of Troops at War's Peak
<em>U.S. Marines begin to form up their convoy at a staging area near Kandahar, Afghanistan, as they await orders to begin their trek to Kandahar to take control of the airfield 13 December, 2001. (DAVE MARTIN/AFP/Getty Images)</em><br><br> Number of U.S. troops in Afghanistan at the war's peak: About 101,000 in 2010. Allies provided about 40,000.
<em>U.S. President Barack Obama delivers a televised address from the East Room of the White House on June 22, 2011 in Washington, D.C. (Pablo Martinez Monsivais-Pool/Getty Images)</em><br><br> Withdrawal plans: 23,000 U.S. troops expected to come home by the end of the summer, leaving about 68,000 in Afghanistan. Most U.S. troops expected to be out of Afghanistan by the end of 2014, though the U.S. is expected to maintain a sizeable force of military trainers and a civilian diplomatic corps.
Number of U.S. Casualties
<em>American flags, each one representing the 4,454 American soldiers killed in the Iraq and Afghanistan wars, move in the breeze at The Christ Congregational United Church March 17, 2008 in Miami, Florida. (Photo by Joe Raedle/Getty Images)</em><br><br> Number of U.S. casualties: At least 1,828 members of the U.S. military killed as of Tuesday, according to an Associated Press count. According to the Defense Department, 15,786 U.S. service members have been wounded in hostile action.
Afghan Civilian Casualties
<em>Asan Bibi, 9, sits on a bench as burn cream is applied to her at Mirwais hospital October 13, 2009 Kandahar, Afghanistan. She, her sister and mother were badly burned when a helicopter fired into their tent in the middle of the night on October 3rd, according to their father. (Photo by Paula Bronstein/Getty Images)</em><br><br> Afghan civilian casualties: According to the United Nations, 11,864 civilians were killed in the conflict between 2007, when the U.N. began reporting statistics, and the end of 2011.
Cost of the War
<em>An Iraqi man counts money behind a pile of American dollars in his currency exchange bureau in Baghdad on April 11, 2012. (ALI AL-SAADI/AFP/Getty Images)</em><br><br> Cost of the war: $443 billion from fiscal year 2001 through fiscal year 2011, according to the Congressional Research Service.
Number of Times Obama Has Visited Afghanistan
<em>US President Barack Obama speaks to troops during a visit to Bagram Air Field on May 1, 2012 in Afghanistan. (MANDEL NGAN/AFP/Getty Images) </em><br><br> Number of times Obama has visited Afghanistan: 3 as president, including Tuesday, and 1 as a presidential candidate.