Sympathizing with Afghan government and people, Bahram Qasemi slammed use of massacre and violence as an instrument.
He also stressed the need for negotiations and maintaining national reconciliation in Afghanistan for achieving peace, stability and tranquility.
The suicide attackers broke into a center for training security forces in Maidan Wardak Province on Monday.
According to local sources, five attackers who were wearing security forces' uniforms detonated a car in front of the building and then started shooting.
There are contradictory reports on the number of casualties.
Some British media like Reuters and BBC announced that 100-120 military forces were killed.
This is while, Maidan Wardak police rejected their reports and said only 20 people lost their lives in the attack.