As news of the attack on the Army Public School in Peshawar spread on Tuesday, people from around the world tuned into to social media sites for information and to vent out their feelings.
With words not sufficient, many changed their display pictures to a patch of solid black colour to mourn the tragedy.
#PeshawarAttack quickly became the topmost trending hashtag across the world with over 350,000 tweets and statements from people, heads of state and celebrities.
The tragedy also saw one of the oldest rivalries in the subcontinent being put aside to show solidarity.
Tehseen Poonawala, hailing from Pune, started the hashtag #IndiaWithPakistan
It soon went viral among Indians and Pakistanis who set aside their animosity for their neighbour to express shock, disbelief and grief over the Taliban attack which left at least 141 people dead including 132 children and nine staffers.
It was soon trending with over 21,000 tweets so far. Here are some of the top tweets: