There have been more than 130 mass shootings across the US so far this year, including the attack at a school in Nashville, Monday in which three children and three adults were killed.
Figures from the Gun Violence Archive - a non-profit research database - show that the number of mass shootings has increased significantly in recent years.
In each of the last three years, there have been more than 600 mass shootings, almost two a day on average.
While the US does not have a single definition for "mass shootings", the Gun Violence Archive defines a mass shooting as an incident in which four or more people are wounded or killed. Their figures include shootings that happen in homes and in public places.
The deadliest such attack, in Las Vegas in 2017, resulted in more than 50 people being killed and 500 wounded.
