On Tuesday, Senator Ted Cruz hit back at Chicago Mayor Lori Lightfoot with a series of tweets after she told him to “keep our name out of your mouth.”

The Chicago Mayor argued that “60% of illegal firearms recovered in Chicago come from outside IL-mostly from states dominated by coward Republicans like you who refuse to enact commonsense gun legislation.” She also told Cruz, “Keep our name out of your mouth.”

Cruz tweeted to Lightfoot and linked a USA Today article showing Chicago as having the most homicides in the U.S. last year: “Mayor, your anger is misplaced. Virtually every year, Chicago has the most murders o any city in America. In 2017, the top five were: Chicago (650 murders), Baltimore (343), Philadelphia (317), New York (290), and Los Angeles (286). All five of those cities have had Democratic mayors for decades and aggressive gun control policies—none seems to be working. Your explanation (“blame Indiana!”) doesn’t hold water. There are 27 states with GOP governors. Chicago is not alone in having neighboring red states. But Chicago’s murder totals are often DOUBLE the next closest city. So how do you explain the big cities in red states, without aggressive gun control laws, where murder rates are MUCH lower than Chicago?”

Cruz continued, “Maybe, rather than getting angry when others point out the tragically high murder rate in Chicago, you put aside the partisan talking points & the failed gun-control policies Chicago has pursued for decades. Instead, lock up the violent criminals who are committing murder… PREVENT felons & fugitives from illegally buying firearms, and ALLOW law-abiding citizens (who are right now obeying Chicago’s prohibition) to exercise their constitutional right to protect their own lives and their families.”

The argument started between Cruz and Lightfoot when Cruz criticized Chicago officials for their gun control policies. “Look at Chicago. Disarming law-abiding citizens isn’t the answer. Stopping violent criminals-prosecuting & getting them off the street-BEFORE they commit more violent crimes is the most effective way to reduce murder rates. Let’s protect our citizens,” the Texas senator wrote.