NEW YORK (CBSNewYork) — Police on Friday were seeking to identify two suspects who chased down a man and punched and kicked him repeatedly on the Lower East Side.

As CBS2’s Valerie Castro reported, the incident was caught on surveillance video. And terrified witnesses could not believe what they saw.

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One witness said the attack was so horrific that he has not been able to stop replaying it in his mind.

What led up to the attack is still unclear. But around 2:45 a.m. Friday, the suspects chased the 24-year-old victim north on Orchard Street toward Stanton Street, police said.

The suspects caught up to the victim in front of 156 Orchard St. and began punching and kicking him in the head, face and body in a vicious and relentless attack, police said.

Video shows the victim protectively covering his head with his hands while the men unleash the kicks and punches.

Despite people walking by, nothing and no one could stop the assault.

CBS2’s Castro spoke to an eyewitness who was so traumatized by what he saw that he did not want to be identified.

“It was really gruesome and hard to watch,” the man said.

The witness and others screamed at the assailants when the violence began.

“And they wouldn’t stop — just going on and on and on, like, and that’s when I was yelling: ‘Stop! Stop! He’s down! Just leave it! Go!’” the witness said.

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No one dared to intervene physically.

“I mean, they were big guys. Like, I myself couldn’t stop them,” the witness said. “I don’t think there was any stopping them.”

Another man in the area saw the emergency crews arrive.

“I saw the ambulance; police surrounding around the situation. I saw the guy actually laying on the floor,” the man said.

“I want the people who did it to get consequences for that. It’s not right,” the first witness added. “That’s a human being.”

The suspects then fled in a black livery car, police said.

The witness said people did step in to help the victim once the suspects ran away. They waited with the man until the ambulance arrived.

The victim was taken to NYC Health + Hospitals/Bellevue in serious condition, police said.

Police have released a surveillance video of the attack.

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Anyone with information was asked to call the NYPD Crime Stoppers at (800) 577-TIPS or (888) 57-PISTA for Spanish, log onto the Crime Stoppers website, or text tips to 274637 (CRIMES) and enter TIP577.