Duckworth was a key speaker at an interfaith prayer event in Chicago's Ukrainian Village on Saturday.
"When you have assault weapons that were designed for war are easily sold at gun shows with no background checks – that is wrong and that is a problem," Duckworth said.
So far this year, about 110 people have been shot and killed in Chicago. About 475 others have been wounded.
Duckworth also reiterated her support of Ukraine as the Russian invasion continues.