"Spoke to PM Nawaz Sharif over the telephone. Offered my deepest condolences on the dastardly terror attack in Peshawar," PM Modi tweeted. (Read full statement here)
PM Modi also offered to provide all assistance to Pakistan "during this hour of grief."
India stands firmly with Pakistan in fight against terror. Told PM Sharif we are ready to provide all assistance during this hour of grief.- Narendra Modi (@narendramodi) December 16, 2014
The PM has also appealed to schools across India to observe two minutes of silence tomorrow as a mark of solidarity.
Mr Sharif has gone to Peshawar. "I can't stay back in Islamabad. This is a national tragedy unleashed by savages. These were my kids," he said in a statement.
PM Modi condemned the attack and said in a statement, "It is a senseless act of unspeakable brutality that has claimed lives of the most innocent of human beings - young children in their school. My heart goes out to everyone who lost their loved ones today. We share their pain and offer our deepest condolences." ("Unspeakable Brutality": PM Modi on Pakistan School Attack)
Amid tension after cross-border violence in Kashmir peaked recently to the worst in over a decade, the two leaders shared cold vibes at a meeting of leaders of South Asian Association for Regional Cooperation or SAARC late last month.
A slight thaw seemed to come as the summit wound up at a mountain retreat where the two leaders shook hands. At a photo-op, PM Modi was seen smiling and chatting with Mr Sharif and at one point placed his hand on Mr Sharif's arm.
But India also cautioned against reading too much into such "courtesies," asserting that it is "for peaceful ties with Pakistan" but wants "meaningful dialogue."
India, however, cancelled secretary level talks in September after Pakistan's High Commissioner in Delhi held consultations with Kashmiri separatists leaders.