U.S. Army Brigadier General Harold J. Greene is pictured in this August 25, 2005 handout photograph, obtained on August 5, 2014. Greene was killed and more than a dozen people were wounded, including a German general, in the latest insider attack by a man believed to be an Afghan soldier, U.S., German and Afghan officials said on Tuesday. REUTERS/U.S. Army/Handout

U.S. Army Maj. Gen. Harold J. Greene has been identified by a U.S. official as the officer killed Tuesday by a man believed to be an Afghan soldier. Greene is the highest-ranking American military officer to be killed in battle since 1970, the Associated Press reported Tuesday evening.

The general was killed by a man dressed as an Afghan military uniform who turned his gun on NATO-led coalition and Afghan forces at a military training academy at the Camp Qargha base west of Kabul. The assailant also shot 15 other soldiers, including "about a dozen" American soldiers -- one of whom was killed in the attack -- a German general and three Afghan army officials, authorities said.

The shooter was killed, Mohammmad Zahir Azimi, an Afghanistan Defense Ministry spokesman, told the AP.

Greene, 55, was appointed to his current post as deputy commanding general for “Combined Security Transition Command” in Afghanistan on Jan. 8, according to the Defense Department. He served the U.S. Army in both Afghanistan and Iraq.

Described as an avid runner who was active in his Falls Church, Virginia, neighborhood, Greene has a son, Matthew, in the army, and a daughter, Amelia, who graduated from Binghamton University recently, the Washington Post reported.

“He was a good guy,” Ret. Army Col. Duane Myers told the Post. “Harry was loved.”

Greene was dedicated to training both U.S. and Afghan security forces, and was known for using cutting-edge technology such as video games and tablet computers to help prepare young soldiers for the modern battlefield, the New York Times reported in 2011.

“We have to adapt to where they are,” Greene told the newspaper at the time. “This is something we absolutely have to do.”

An upstate New York native with two brothers, Greene graduated from Rensselaer Polytechnic Institute in 1980 before going on to earn master’s degrees in engineering from both RPI and the University of Southern California; a master’s degree in strategic studies from the U.S. Army War College; and a Ph.D. in materials science from USC, according to a U.S. Army bio of the distinguished general.

He was a highly-decorated officers with awards including the Legion of Merit, the Meritorious Service Medal with a silver cluster, the Army Commendation Medal, the Army Achievement Medal and the Army Superior Unit Award, according to his Army bio.

The Pentagon did not publicly identify Greene earlier because his family had yet to be notified, Pentagon spokesman Rear Adm. John Kirby said, according to ABC News.

President Hamid Karzai said the soldiers were at Camp Qargha to help build the Afghan security forces.

Karzai immediately condemned the attack on Tuesday, blaming it on "enemies who don't want to see Afghanistan have strong institutions."

The shooting spree falls under the category of what is called a “green-on-blue attack,” in which an Afghan policeman or soldier fires on coalition forces in Afghanistan. Once a fairly common incident in Afghanistan -- which saw 44 such attacks in 2012 resulting in 15 percent of that year’s coalition deaths in the Middle Eastern nation -- Tuesday’s assault marked just the third “green-on-blue attack” so far in 2014.

"We are in the process of assessing the situation," the ISAF Joint Command said in a statement. "More information will be released as we sort out the facts."