A day after a lethal Taliban assault on an army base in northern Afghanistan, an official said on Saturday that at least 140 soldiers had been killed, making it the single deadliest known attack on an Afghan military base in the course of the long war.

The soldiers, most of them unarmed, were shot while eating lunch or emerging from a Friday Prayer service at the headquarters of the Afghan Army’s 209th Corps in Balkh by assailants in military uniforms who entered after another attacker had detonated explosives at a check post. The Taliban claimed responsibility for the assault, reported The New York Times.

“Today, there was even a shortage of coffins,” said a senior official, Ibrahim Khairandish, a member of the provincial council in Balkh Province, where the attack occurred.

Citing information from army officials, Khairandish said 60 soldiers had also been wounded in the attack.

According to him, Taliban fighters dressed in military uniforms raided an army base in northern Afghanistan, raking it with gunfire in an hours-long attack that killed or injured more than 100 soldiers, said a report citing senior officials.

The attack started as soldiers were observing Friday prayers at Camp Shaheen near Mazar-e Sharif, the country's third-largest city, reported CNN citing senior Afghan military officials.

The Taliban released the names and a picture of 10 men who they said had taken part in the assault. All were dressed in Afghan military uniforms, down to helmets and kneepads, said the NY Times report.

A Taliban spokesman, Zabihullah Mujahid, said the assailants had been led inside the base by four soldiers who had long been working for the militants.

Dawlat Waziri, an Afghan Ministry of Defense spokesman, declined to give a more precise accounting of dead and injured but said one would be released later.

The uniformed attackers entered the base in vehicles and opened fire, Afghan army spokesman Abdul Qahar Araam said. The gunfire was followed by an explosion at one of the base's gates, it stated.

The attack lasted six hours. By the end, at least five attackers were killed, and one was arrested, Araam said.

Afghan President Ashraf Ghani has declared Sunday a national day of mourning in remembrance of the Afghan forces killed on the base. The national flag will be flown at half-staff in Afghanistan and its missions.

The base is the headquarters of the 209th Shaheen Corps in Balkh province.