Shocking: 13-year old boy shot his 12-year old sister with their dad's gun on Facebook live.

A 13-year-old boy accidentally shot dead a 12-year-old girl on Facebook Live while playing with a shotgun.

The children were playing with friends in a house in Santa Rosa de Calchines, in Argentina's Santa Fe province when the tragedy happened.

Footage captured by one of the youngsters in the room shows the boy pointing his father's gun at the girl, named locally as Georgina Magalí Vega. Believing it to be unloaded, he can be seen pulling the trigger a number of times.

But seconds later, and with the camera pointing away, the harrowing video captures the sound of a shot. It later emerged that Georgina had been killed instantly when the weapon was fired.

According to local reports, the horrifying incident unfolded on Facebook Live in the middle of the afternoon.

At the beginning of the clip, the boy can be heard saying 'Look at this. A shell. I load it and I shoot you but you don't die.'

Dailymail U.K.