NEW YORK (CBSNewYork) — Officers from the New York City Department of Correction on Wednesday called on their commissioner to resign following a series of attacks in city jails.

One of the assaults was caught on camera, and now they’re demanding Mayor Bill de Blasio take action to keep their people safe.

Video from the attack in Brooklyn shows a detention officer standing next to an open cell block. Before long, a prisoner walks up and gets in the guard’s face. More inmates followed, before one of them started to punch the guard over and over again in a relentless barrage. He even put the guard in a choke-hold and threw him onto the ground and proceeded with another flurry of fists.

The officer was left lying on the ground, bloodied and not moving as the intimidating inmate walked off.

“He was beaten pretty badly,” said Elias Husamudeen, president of the NYC Correction Officer Benevolent Association. “He’s in the hospital. He has a concussion but he’s still there under observation. I don’t believe his nose is broken but he definitely has a concussion.”

A photo shows that guard’s bruised and bloodied face as he lay in a hospital bed.

Another guard was attacked July 13 on Rikers Island.

The Department of Correction says those inmates were re-arrested and moved to restrict housing.

The Correction Officers’ Benevolent Association says it’s the third assault on one of their own in just two weeks. And they want the violence stopped.

“It’s time for [Department of Correction] Commissioner [Cynthia] Brann to go and it’s time for Mayor de Blasio to do his job and give us back punitive segregation,” said Husamudeen. The union president told reporters Wednesday that without pulling troublemakers aside, attacks like this one will never stop.

“When these inmates attack us and when they’re violent, we’re able to segregate them. We’re able to move them away. Keep them away from us, keep them away from inmates,” said Husamadeen.

“The other thing is the mayor has taken away disciplinary sanctions that we once had the ability to use against inmates that also helped to keep them in line,” he said.

Commissioner Brann released a statement in response Wednesday, saying in part, “We are making use of all the tools available to us to help keep officers safe and give them the support they need to carry out one of the most difficult jobs in this city, and any claim otherwise is utterly false.”

But until more is done, the union says it will continue to fight for these officers.