Four people were killed and seven others were wounded in a shooting at an Independence Day celebration in Shreveport, Louisiana, on Tuesday night, authorities said. Officers responded to a call of shots fired shortly before midnight at a gathering in the northwest section of the city, Sgt. Angie Willhite of the Shreveport police said Wednesday. One gunman opened fire at a gathering of about 100 people. No arrests have been made so far. A total of 16 mass shootings took place across the nation from Friday until Wednesday morning, leaving 15 dead and 94 injured, according to the Gun Violence Archive.