The child rights crusader who along with Pakistani teenager Malala Yousafzai received the Nobel Peace Prize termed the attack in Peshawar as one of the darkest days of humanity.

"My heart is in Peshawar where the incident happened, even though I am not physically present there. It is the most tragic event which has occurred in history of the world," Satyarthi said.

"When I learnt about what was happening in Pakistan, my first reaction was that those terrorists should leave those 400 kids of mine and take me as a hostage instead. But by then we learnt that over 100 children had already been killed by them," he added.

Expressing his anguish at the act of brutality, Satyarthi appealed to the terrorists groups to spare lives of innocents.

"These are acts of sin, against any religion. They should remember their own childhood, life under their parents and spare young children with this thought. No religion allows for the killing of innocent beings," Satyarthi added.

He was speaking at an event organised by the German Embassy here in collaboration with NGO 'The Hope Project' which has launched a project to teach computer skills to girls.

Satyarthi also strongly advocated making concerted efforts for ensuring education for girls, saying it was key for a harmonious society.

"Education of girls is highly necessary, not just because we're living in the world of information, technology and need to stay updated but because we want to create a world which is connected together and that cannot exist without education," he said.     

German Ambassador to India Michael Steiner also condemned the attack and said children of the entire world are in solidarity with Pakistan.

"This was a heinous crime. But I must say that the whole world is united, the kids in India, the kids in Pakistan, the kids in Europe, the kids in United States everywhere in this world, we are united in condemning this attack.

"What we did today here is to try to give kids in India a future. This act was to take away this very future but we need to make sure that we give these kids a future," the ambassador said.

The German Embassy has donated four computers to the Hope Project specifically meant for the education of girls studying as a part of the non-formal study program in the organisation. In fact, one of the systems given away was being used personally by the Ambassador in his office.

Satyarthi and the German Ambassador were seen talking to the young girls about their activities at the schools.

Satyarthi even wrote down his email address for the young girls, asking them to write to him, promising gifts in return.

During the interaction with the girls, the Bachpan Bachao Aandolan-founder shared a story about Shazia, a survivor of the same attack on Malala Yousafzai after meeting a young girl from the NGO of the same name.

"During the Nobel Prize ceremony I asked Malala, that she is like my daughter and would she accept me as her father, she promptly said yes and called me her new father.     

Shazia and Kainaat, the other two survivors of the attack on Malala were also present at the ceremony. So, after sometime Shazia and Kainaat came to me and asked me sweetly, if they could also call me 'Abu' (father)?, Satyarthi fondly shared.