Taliban insurgents said on Monday they would observe a three-day ceasefire in Afghanistan for the Muslim religious holiday of Eid, starting this week, after weeks of increasing violence that gripped the country. "In order that the Mujahideen again provide a peaceful and secure atmosphere to our compatriots during Eid-ul-Fitr so that they may celebrate this joyous occasion, all Mujahideen ... are instructed to halt all offensive operations," Mohammad Naeem, a Taliban spokesman, said on Twitter. Eid will begin on Wednesday or Thursday this week depending on the sighting of the moon. The ceasefire declaration came two days after bombings outside a school in the western part of the Afghan capital, Kabul, killed at least 68, most of them students, and injured more than 165 others. No group claimed responsibility for the attack. Taliban insurgents, fighting to overthrow the Afghan government since their ouster by U.S.-led forces in late 2001, denied involvement in the bombings and condemned them. Afghan government leadership said the group was behind the attack. Naeem said the group"s fighters had been instructed to cease all military operations against the Afghan government, but added they were ready to retaliate if attacked by government forces. Fraidoon Khwazoon, a spokesman for Abdullah Abdullah, chairman of Afghanistan’s High Council for National Reconciliation, which heads the peace process, said the group welcomed the Taliban"s ceasefire announcement. President Ashraf Ghani"s spokesmen were not immediately available to comment on whether they would observe the ceasefire. Peace talks between both warring sides in the Qatari capital, Doha, which began last year, have made no progress and violence has risen. Kabul has been on high alert since Washington announced plans last month to pull out all U.S. troops by Sept. 11, with Afghan officials saying the Taliban stepped up attacks across the country following the announcement.