The Taliban has declared a three-day ceasefire across Afghanistan, to mark Eid al Fitr, only two days after more than 50 people - most of which were young girls - were killed in bomb blasts outside a school in Kabul.

A statement from the Taliban on Monday read "Mujahideen of the Islamic Emirate are instructed to halt all offensive operations against the enemy countrywide from the first till the third day of Eid".

“But if the enemy conducts any assault or attack against you during these days, stand ready to robustly protect and defend yourselves and your territory,” the statement added.

A statement from Pakistan's Ministry of Foreign Affairs read, "We welcome the three-day ceasefire announcement for Eid-ul-Fitr by Taliban. We fully support all efforts that lead to reduction in violence and contribute to achieving durable stability & lasting peace in Afghanistan".

The ceasefire announcement comes as the United States continues to withdraw its last 2500 troops from the war-torn country, as negotiations between the government and the Taliban falter.

The Taliban has previously declared similar ceasefires to mark Muslim holidays.

Fraidon Khawzon, spokesman for chief negotiator Abdullah Abdullah, stated on Monday “We welcome the announcement … the Islamic republic is also ready and will announce soon".

Afghan President Ashraf Ghani declared Tuesday a day of national mourning, stating that “This savage group does not have the power to confront security forces on the battlefield, and instead targets with brutality and barbarism public facilities and the girls’ school".

The Taliban, who denied responsibility, issued a statement saying the nation needed to “safeguard and look after educational centres and institutions”.