Nasratullah Jamshidi, said the attacker, an Afghan commando, had been shot at the scene and died on his way to a hospital.
But he confirmed that seven soldiers had been evacuated after being wounded in the incident at Camp Shaheen, the headquarters of the Afghan army's 209th Corps in the northern city of Mazar-i-Sharif.
"At this time, we can confirm there are no USA or NATO Resolute Support fatalities", the mission said in a statement.
The increase in insider attacks in recent months has anxious coalition officials.
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One Afghan soldier was killed and another was hurt in the attack that occurred around 2 pm.
Taliban claimed responsibility for that attack.
Meanwhile, India's ambassador to Kabul, Manpreet Vohra, also addressed guests at the ceremony and said India hopes this corridor will grow to one day become an air corridor network. At least five security forces and several civilians were killed, officials said. Details of the attack are still classified but according to reports, an Afghan soldier opened fire on a group of American soldiers in training and wounded seven.
U.S. troops are also at risk in other parts of Afghanistan.
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The NATO-led Resolute Support Mission said in a statement that no USA soldier died in the assault, while the attacker was killed in a retaliatory fire.
Afghan policemen gather at the site of an attack Sunday in Gardez.
Last week three USA soldiers were killed by an Afghan soldier in eastern Nangarhar province.
As Pakistan begins to reassert itself in Afghanistan as evidenced by the spiralling violence, India is making a move to deepen its economic linkages with the war-torn country with the start of an air freight service connecting New Delhi and Kabul that is also aimed at stabilizing the fragile Afghan economy.
Sunday's attack came a day after an Afghan commando fired on USA troops, wounding seven American soldiers. The convoy returned fire in self-defense, and there were no United States casualties, North Atlantic Treaty Organisation said in a statement.
Most of the troops will help train or advise Afghan forces, while a smaller number of troops will be dedicated to "counterterror operations against the Taliban and IS", according to the Post.
The insurgents are also targeting the global coalition supporting Afghan forces.
U.S. troops in Afghanistan now number about 8,400, with another 5,000 from North Atlantic Treaty Organisation allies.