A little over a month ago, the massacre at an elementary school in Texas shook the United States to its foundations. Now a gunman opens fire in the middle of the national holiday.

A gunman opened fire at a US National Day parade in a suburb of Chicago, killing at least six people.

A police spokesman said 24 people were taken to hospitals after the crime in Highland Park, Illinois. The shooter was initially not caught. A weapon was found at the crime scene. The suspect is described as a white male between the ages of 18 and 20. A spokesman for the Lake County Sheriff’s Office said it appears the gunman fired from a rooftop.

Mayor Nancy Rotering urged people to avoid downtown. The administration of the small town with around 30,000 inhabitants said: “Numerous police officers are on duty and have cordoned off downtown Highland Park.”

Eyewitness: Heard around 30 pops

The background to the fact is not yet known. An eyewitness named Miles Zaremski told CNN that he saw several injured and lifeless people lying on the ground. “It was heartbreaking.” He heard around 30 pops. People fled the parade. “It was just chaotic.” Mayor Rotering announced that the 4th of July festival had been cancelled. The United States celebrated its Independence Day on Monday.

The US has long struggled with massive levels of gun violence. At the end of May, an 18-year-old gunman massacred a Texas elementary school. He had killed 19 children and 2 teachers in the small town of Uvalde at the end of May before he was shot dead by the police. The crime had rekindled the discussion about stricter gun laws in the USA. Firearms are relatively easy to obtain in the United States.

Congressman Brad Schneider, who wanted to attend Monday’s parade, wrote on Twitter: “My condolences to the family and loved ones.” He is committed to doing everything “to make our children, our cities and our country safer. Enough is enough!”