Two so-called insider attacks, in which a soldier in an Afghan National Army uniform turns his weapon on foreign troops, in as many weeks have killed three US soldiers and wounded another seven.
The US soldiers were evacuated after the "insider attack" a spokesman for the US military command said.
The attack on Saturday took place at the Afghan National Army's 209th Corps headquarters in the province of Balkh, located some 540 km to the northwest of Kabul. Two attackers were immediately killed by the Afghan forces while one attacker is absconding.
NATO's Resolute Support later tweeted that seven USA servicemembers were wounded and evacuated for treatment. A ten man strong team dressed in Afghan military uniforms killed more than 140 Afghan soldiers using both gun fire and bomb blasts.More news: Kiwis beat Oracle in 1st 2 America's Cup races in Bermuda
Taliban claimed responsibility for that attack.
Of the seven attackers involved, one blew himself up in a auto at the entrance to clear the way for the others to rush into the building, the office of the Paktia provincial governor said in a statement announcing the end of the raid.
A week ago three U.S. soldiers were killed and a fourth wounded when an Afghan soldier opened fire on them at a base in eastern Afghanistan's Nangarhar province. -Afghan military operation in the country's Achin district.More news: WBC heavyweight champ Deontay Wilder charged with marijuana possession
He says two of the attackers were shot by security forces and probably one more attacker is still resisting.
Saturday's incident comes just days after President Donald Trump delegated authority to Defense Secretary Jim Mattis to set USA troop levels in Afghanistan, opening the door for a possible of influx of forces that could number in the thousands.
"Initial information shows three U.S. soldiers visiting the base were wounded", defence ministry spokesman Mohammad Radmanish told AFP, adding that the attacker had been gunned down. It is also used by allied groups such as the Movement of the Taliban in Pakistan, Lashkar-e-Taiba, the Islamic Movement of Uzbekistan, Shabaab, and by the rival Islamic State.
Islamabad said Afghanistan had formed three different investigating groups to probe the incident. There has been no causality reported by the US Troops.More news: US official makes brief appearance at G7 environment summit