Despite enhanced security screening in the morning, scattered violence took place along the route of the West Indian Day parade in Brooklyn Monday afternoon as revelers complained of smaller than normal crowds.

Parade-goers had waited in the predawn hours to get through the screening at Brooklyn’s Grand Army Plaza as the J’Ouvert celebration got underway. Those festivities, plagued by violence in past years, went on peacefully.

But hours later, an assault, a stabbing and a shooting took place along the West Indian Day parade route, authorities said.

A male was assaulted along the route about 3:35 p.m. and taken to Kings County Hospital with injuries that were not life-threatening, the NYPD said.

Then at about 4:45 p.m., a 22-year-old man was shot in the torso along the parade route on Eastern Parkway, police said. He is in critical but stable condition, the NYPD said.

At 6:15 p.m., a man, 20, was stabbed in his left abdomen in front of 667 Eastern Parkway and taken to the New York-Presbyterian Brooklyn Methodist Hospital, police said.

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No arrests have been made and police were investigating.

Everyone attending J’Ouvert had to go through a checkpoint on Flatbush Avenue. Police scanned people with handheld metal detectors and searched bags for any contraband and weapons.

Deryck Jones, 52, of Canarsie, said he has been going to the parade for 30 years and that this year’s crowd was the smallest he’s ever seen — what seemed to him to be a few thousand people.

“This wasn’t that good. This wasn’t that good at all,” he said as the march neared the end. “There were too many restrictions. I don’t feel energized. I’m trying the best to feel it, but I’m not feeling up the culture.”

City Councilman Jumaane Williams, who represents the Flatbush area, said he was disappointed in the smaller crowd.

“We definitely have to do a debrief and figure things out,” Williams said as he marched. “There might have been some issues with security that kept people away. And that needs to be addressed.

“It’s a pendulum that swings back and forth, and we have to find a medium,” he continued. “Some people’s spirits are down, but there’s a lot more out and having fun.”

Yvette Rennie, president of J’Ouvert City International, said the increased police presence worked well, for the most part.

“It went excellent. It was beautiful,” Rennie said. “It worked. The only thing is the time at checkpoints took a while, but it did work. . . . Naturally, you’ll have those who don’t like the changes, but there is a larger percent who do.”

The stepped-up police presence was evident in the squad cars, sanitation trucks and vans parked on streets illuminated by spotlights.

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With J’Ouvert starting at 6 a.m. — two hours later than in past years to allow for more daylight — the crowd still stretched down Flatbush Avenue, with many wearing costumes and talking as they calmly waited to get past security.

The West Indian Day parade, which draws an estimated 3 million spectators who come to marvel at the myriad floats and costumes celebrating Caribbean culture, began at 11 a.m. on Eastern Parkway in Crown Heights.

Violence has erupted during J’Ouvert in recent years, leading to injuries and some deaths. In 2016, St. John’s University student Tiarah Poyau, 22, was struck and killed by gunfire at the end of the festival. A suspect, Reginald Moise, now 21, was arrested on charges including second-degree murder and is awaiting trial.

Tyreke Borel, 17, also was killed by gunfire as he sat on a bench near the celebration. Two other people were injured by gunfire during that year’s festival.

In 2015, Carey Gabay, 43, an attorney who was an aide to Gov. Andrew M. Cuomo, died days after being struck by a stray bullet from a gang shootout as he ducked for cover.

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After the killings, some critics called for an end to J’Ouvert. But parade organizers, city officials, police and neighborhood groups last year worked out the latest security precautions.

With Maria Alvarez, Ellen Yan and Anthony M. DeStefano