A gun-safety group from Boston is taking aim at loopholes in gun laws and Congress for not doing enough to protect people from gun violence.

“For too long, Congress has been ignoring the numbers,” said John Rosenthal, chairman of Stop Handgun Violence.

Rosenthal and others attacked legislators who took nearly $7 million in lobbying contributions from the National Rifle Association in 2010.

The group unveiled its latest billboard overlooking Interstate 90 in front of Fenway Park.

A digital counter on the billboard will increase by eight each day to mark the number of teens or children killed by guns.

While Massachusetts is a leader in gun-violence prevention, advocates said illegal guns are making their way here from surrounding states with little or no restrictions on sales.

The group had the support of state and local law enforcement officials and mothers who spoke in support of the efforts of Stop Handgun Violence.

Tina Chery’s son, Louis Brown, was killed by a stray bullet in 1993 while walking in Dorchester.

“Where Louis was killed, nothing has changed,” she said, adding that efforts need to focus on families as well.