Newtown dad Neil Heslin weeps at US Senate hearing

The father of a boy killed in a mass school shooting in December has broken down in tears at a US Senate hearing on a proposed assault weapons ban.

Neil Heslin said he came to "speak up" for his six-year-old son Jesse, who died along with 25 others in Newtown, Connecticut.

Opponents of the bill say it would violate the right to bear arms.

The massacre fuelled debate on how to curb America's gun violence epidemic, but it is unclear if lawmakers will enact stricter gun control.