New Zealand Prime Minister John Key said on Saturday that the loss of life in the school shooting in Connecticut, the United States, is heart-breaking.

Twenty schoolchildren and six teachers were massacred on Friday, US local time, when a young gunman walked into a quiet Connecticut primary school.

Key expressed dismay at the random, needless and heart-breaking loss of life at the elementary school.

He sent his heart-felt condolences to the families of the victims, the staff of the school, and the Newtown community.

Leaders from many countries are expressing sympathy to the families of the victims of the tragedy.