Republican Sen. Marco Rubio was put on the defensive Wednesday by angry students, teachers, and parents who are demanding stronger gun-control measures after the shooting rampage that claimed 17 lives at a Florida high school.

One of those confronting the Florida senator at a CNN's "Stand Up" town hall Wednesday night was Fred Guttenberg, whose 14-year-old daughter Jaime was killed on Feb. 14 with 16 others. Rubio was the lone Republican at the nationally broadcast gathering after Florida's GOP Gov. Rick Scott and President Donald Trump declined invitations to appear at the event in Sunrise, Florida.

Guttenberg told Rubio that his comments about the shooting "and those of your president this week have been pathetically weak."

People stood up and cheered Guttenberg as he challenged Rubio to tell him the truth, to acknowledge that "guns were the factor in the hunting of our kids."

Guttenberg added, "And tell me you will work with us to do something about guns."

Rubio responded that the problems laid bare by the shooting rampage "cannot be solved by gun laws alone," drawing jeering whistles from the crowd. Rubio responded that he would support laws barring those 18 and under from buying such weapons, support changing the background checks system and getting rid of bump stocks.