Updated at 10:02 p.m. ET Sunday

A U.S. service member was killed and two others wounded in what NATO and Pentagon officials are calling "an apparent insider attack" in southern Afghanistan.

In a statement on Sunday, the Pentagon identified the dead solider as Cpl. Joseph Maciel of South Gate, Calif. He died Saturday "from wounds sustained during an apparent insider attack" in Tarin Kowt District, Uruzgan Province, Afghanistan.

Maciel was part of the newly-established 1st Security Force Assistance Brigade, deployed to train Afghan fighters.

Details of the incident, which is still under investigation, were not released.

"Maciel was an excellent soldier beloved by his teammates and dedicated to our mission," Lt. Col. David Conner, Maciel's battalion commander, told the Ledger-Enquirer. "He will be greatly missed by the entire Black Lion family. Our prayers are with his family and friends during this difficult time."

Maciel's honors include the Army Achievement Medal, National Defense Service Medal and Army Service Ribbon, the Columbus, Ga., newspaper site says.

On Saturday, NATO's Resolute Support mission said the two U.S. service members wounded in "an apparent insider attack" are in stable condition.

The Taliban released a statement on Twitter saying an Afghan soldier fired on U.S. troops in the province of Uruzgan, AFP reported. The militant group acknowledged the attack but did not claim responsibility.

"A patriot Afghan soldier opened fire on Americans in Uruzgan airport killing and wounding at least four American invaders," the Taliban said.

The attack comes a year after an Afghan soldier killed three U.S. service members during what was a joint operation.

Insider attacks are commonly referred to as "green on blue" attacks. They happen when "Afghan service members or attackers wearing Afghan uniforms fire on U.S. or coalition troops," Reuters notes, adding that such attacks "have been a regular feature of the conflict in Afghanistan, although their frequency has diminished in recent years."

The U.S. had more than 13,000 uniformed service members in Afghanistan as of fall 2017. But as NPR's David Welna reported last week, a "public information blackout" by the Trump administration has meant that, "since late last year, the Pentagon's stopped posting those numbers for Iraq, Syria and Afghanistan."

NPR's Tom Bowman noted last month that "a permanent end in the fighting does not seem to be anywhere in sight" in Afghanistan. "The Taliban have gained ground, U.S. airstrikes have spiked to put pressure on the group to negotiate, and civilian casualties have increased — partly due to those airstrikes but mostly because of Taliban attacks, and some ISIS attacks."

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