Afghan government officials say the death toll has jumped to 140 following Friday's assault on an army base in the northern Balkh province.
Another 160 people were wounded in the attack, Mohammad Ibrahim Khair Andesh, the head of the provincial council, announced on Saturday.
The attack, responsibility for which has been claimed by the Taliban, happened at an army command centre a few miles from Mazar-i-Sharif, the capital of Balkh.
Two of the attackers blew themselves up and seven were killed in the assault, which lasted several hours and targeted soldiers at a mosque and a dining facility, the Afghan defence ministry said.
One of the assailants was detained.
"There were about 10 fighters. One of them detonated his explosives and another went head. That's when the firefight erupted," Ghulam Hazrat, a witness, told Al Jazeera.
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"There were two checkpoints but the fighters managed to go through that, as well. It was chaotic and I saw more than 60 people dead on the spot.
"The toll is still rising because it was a large-scale attack. People are in fear and have a lot of questions."
Fighters in three military vehicles with forged documents launched the attack by shooting a rocket at the entrance of the base, a military official told DPA news agency.
The source said 10 fighters first targeted the mosque, where army staff were performing Friday prayers, before moving on to the dining facility, the source said.
Several military helicopters hovered over the facility during the attack and ambulances later took away the bodies of the victims, an AFP news agency correspondent said.
The Taliban claimed that more than 500 soldiers were killed and wounded.
The group also claimed that four of the attackers were soldiers who had served at the base and had knowledge of the facility.
Zabihullah Mujahid, Taliban spokesman, claimed responsibility for the assault.
"Our fighters have inflicted heavy casualties on the Afghan army stationed there," he said.
The Taliban released a picture of the purported attackers, dressed in military gear, with their faces blurred.
"During Friday prayers, the mosque here would be very busy. Several hundred people would come in from other places, as well," an Afghan national who serves in the army told Al Jazeera on condition of anonymity.
"So, this was a well-planned attack. There is a possibility, as well, of insiders helping the fighters. Otherwise, how can someone attack a large military base with such heavy security?"
He said two attackers detonated their suicide vests, and after that eight others went further and launched a gun battle. They killed most of my friends."
"Our government is lying and not being clear about the death toll. It was a massacre."
The base in Balkh is home to the Afghan army's 209th Corps, as well as to a contingent from the German army. No German soldiers were affected by the attack.
'Few thousand troops'
General John Nicholson, the top US commander in Afghanistan, praised Afghan commandos for bringing what he called Friday's "atrocity to an end".
In February, he told the US Senate Armed Services Committee in Washington, DC that he needed "a few thousand" more troops to help train and assist the Afghan forces.
The US has about 8,400 troops in the country, with about another 5,000 from NATO allies assisting a much larger Afghan force in the war against the Taliban and other armed groups.
The last major attack against a military site in Afghanistan was in early March when fighters disguised as doctors stormed the Sardar Daud Khan hospital - Kabul's largest military hospital - in Kabul, killing dozens.
Afghan security forces, beset by killings, desertions and non-existent "ghost soldiers" on the payroll, have been struggling to beat back the Taliban since US-led NATO troops ended their combat mission in December 2014.
According to US watchdog SIGAR, casualties among Afghan security forces rose by 35 percent in 2016, with 6,800 soldiers and police killed.
Source: Al Jazeera and news agencies