The shootings killed three men and wounded three men and two teenage boys, altogether.
In the most deadly of the three shootings, two men were killed and three men were wounded in an attack "linked to vicious gang activity," Superintendent Michael Harrison said. He did not give details.
Witnesses described a fusillade of bullets that targeted men in a car outside a house where a party was going on a few miles from the parade route and hours after Tuesday's last parade.
Two afternoon shootings on the parade route started with fights among "friends and known acquaintances," Harrison said during a news conference livestreamed on the department's Facebook page .
"That could have happened anywhere," he said.
The first one wounded two teens, who were in a group of about 10 people when one of them began shooting, police said in a news release.
The second shooting killed a man, identified Wednesday by the coroner's office as Maurice Williams, 29. He got into an argument that turned into a fight with an acquaintance who pulled a gun, police said.
Police were nearby both times and arrived quickly, giving first aid and securing the scene, Harrison said Wednesday.
He also said officers arrested 53 people for illegally carrying guns and confiscated 48 firearms along parade routes and in the French Quarter during the two weeks from the start of the Carnival season through Fat Tuesday. Another 48 guns were confiscated in the rest of the city, he said.
"That we were able to make so many gun arrests without injury and without force ... is a tremendous compliment" to the department's officers, he said.
Police have a warrant for 21-year-old Eddie Dingle in Williams' death and have released a photo of a possible suspect in the other parade-route shooting, which wounded two teenage boys.
The coroner's office said Byron Jackson, 21, and Jamar Robinson, 26, were killed in the nighttime shooting in the Lower 9th Ward about 2 miles (3 kilometers) from the parade route.
Police spokeswoman Ambria Washington said multiple suspects opened fire on a car with five people inside. The gunfire shattered its windows, flattened its front tires and left more than a dozen bullet holes in the driver's door.
The driver managed to drive to a nearby gas station before two people died from their wounds. Arriving officers strung up police tape to keep crowds away. At that scene and outside the family home of some of the victims a few blocks away, mourners were still wearing festive Mardi Gras shirts and hats.
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