President Ashraf Ghani ordered Sunday a national day of mourning in honor of the dozens of soldiers killed in the Afghan National Army 209 Shaheen Military Corps Headquarters in Dehdadi district in Balkh on Friday afternoon.

At least 135 soldiers are believed to have been killed in a massive attack by the Taliban on the heavily fortified military base.

Government has not however released official figures on the death toll but the ministry of defense said on Saturday that about 100 soldiers had been killed and wounded.

In a decree issued on Saturday night, Ghani ordered Sunday a national day of mourning and said all Afghan flags must be flown at half-mast for the day.

“Special mourning ceremonies must be held at the Presidential Palace and all mosques in the country for the day,” he said in the statement.

Ghani held an emergency meeting with senior officials from the 34 provinces via video conference where he discussed the situation.

Ghani said investigations into the deadly incident had started and that the deputy minister of defense, the deputy head of the national directorate of security and the chief of army staff are at the scene of the attack in order to carry on the probe.

He added that measures have been taken to transfer the bodies of fallen soldiers to their families.

The Ulema Council of Afghanistan meanwhile issued a statement and strongly condemned the attack and called it “against all human and Islamic principles.”

“Attacking Muslims in mosques while they are praying has no Islamic and human justifications,” it said, adding that “it’s not the first time that the insurgents target mosques, funerals and even Holy Quran ceremonies,” the statement read.

“The insurgents carry out such crimes in the name of Islam but such attacks are completely against Islam and is in clear hostility with Islam,” it said.