More than 100 Afghan soldiers were killed or wounded as Taliban fighters attacked an army base during Friday prayers.
Ten militants - dressed in army uniforms - attacked the headquarters for the Afghan army's 209th Corps near Mazar-i-Sharif in Balkh province.
Two blew themselves up shortly after entering Camp Shaheen and the others died during a battle lasting several hours.
"The majority of our soldiers were offering Friday prayers" at the time of the assault, the ministry said in a statement.
"Over 100 Afghan army forces were martyred and wounded."
However, a military official has told AFP that "150 soldiers were killed and dozens wounded".
"They were young recruits who had come for training," he said on condition of anonymity.
The Taliban claimed responsibility for the attack, saying: "Our fighters have inflicted heavy casualties on the Afghan army stationed there."
The base is and a number of foreign soldiers are also based there as part of a NATO-led mission to train Afghan security forces.
The US and German military have both said no international troops were involved in the attack but it is unclear how close soldiers were to the fighting.
The Afghanistan government is locked in an ongoing battle with Taliban insurgents and other militant groups within the country.
The NATO command in Kabul called the attack "murderous and reprehensible".