At a rally for his presidential campaign Saturday, Independent Vermont Sen. Bernie Sanders addressed the recent rash of shootings on American college campuses and recommended policies to curb gun violence.

Sanders said a ban on assault weapons as well as expanded background checks for gun buyers and stronger mental health infrastructure were “commonsense approaches, which in fact the vast majority of the American people support.”

Speaking to a crowd of about 9,000 people at the University of Colorado in Boulder, Sanders offered his condolences to families of the victims of the last week’s shooting in Roseburg, Oregon and Friday’s shootings on college campuses in Arizona and Texas.

The candidate for the Democratic nomination echoed President Obama’s statement on the shooting, saying, “We’re all getting pretty tired of condolences and prayers after mass killings.”

“Condolences and prayers are not enough,” Sanders said. “We have got to do something meaningful to address this crisis” of gun violence.

We are tired and we are embarrassed seeing children in elementary schools slaughtered and young people on college campuses shot. — Bernie Sanders (@SenSanders) October 11, 2015

“Instead of people yelling at each other, we have got to come together on commonsense approaches,” including a ban on semi-automatic assault weapons, which he called, “guns which have no other purpose but to kill people.”

Saturday was not the first time Sanders has come out in favor of such a ban: He voted for a 1994 assault weapons ban and in 2013, in the wake of the Sandy Hook school shooting in Newtown, Connecticut, he supported an assault weapons ban and enhanced background checks for gun buyers, both of which failed in the Senate.

But Sanders’ record on gun control is mixed, and may be one of the few policy areas in which his opponents in next week’s Democratic presidential debate can attack the socialist lawmaker from the left.

As a candidate for a House seat in 1990, Sanders won the tacit support of the National Rifle Association and other gun rights groups by opposing a measure that would establish a waiting period for handgun sales. The NRA targeted Sander’s opponent in the race, incumbent Republican Peter Smith.

In a pre-election letter to its Vermont members, the NRA said, “Bernie Sanders is a more honorable choice for Vermont sportsmen than ­Peter Smith,” according to the Washington Post.

Sanders won the race, but fell out of favor with the NRA following his later support for some gun control measures, which prompted the organization to give his record on gun issues a “D-minus” grade.

Sanders portrays himself as a moderate on gun issues and says that issues around guns in his largely rural state differ from those in other parts of the country.

“Guns in Vermont are not the same as guns in Chicago, or guns in Los Angeles. In our state, guns are used for hunting; in Chicago they’re used by kids in gangs killing other kids, or people shooting at police officers,” Sanders said in a July appearance on CNN’s “State of the Union.”

Sanders’ Democratic campaign opponents have already taken aim at his record on gun control.

Former Maryland governor and Democratic presidential candidate Martin O’Malley released a campaign ad that called Sanders “no progressive when it comes to guns,” and both O’Malley and Hillary Clinton have made gun control visible parts of their campaign policy proposals.