What to Know Four Port Authority police officers are being credited as heroes after diving on a suspect in Monday morning's bombing in Manhattan

The officers heard the blast and called for help; when they arrived on scene, officials said they saw the suspect reaching for his phone

The suspect, Akayed Ullah, was the only one seriously injured in what Mayor de Blasio called an attempted terror attack

When the violent rumble of a crude explosive detonating sent hundreds of commuters running in a crowded tunnel near Manhattan’s Port Authority Bus Terminal, four officers did what they were trained to do: They headed to the source of the sound.

Port Authority Police Department officers Jack Collins, Anthony Manfredini, Drew Preston and Sean Gallagher were credited with saving dozens of lives after the blast in a tunnel between the Port Authority/42nd Street subway station and the Times Square/42nd Street stop on Monday morning by jumping on the suspect in the attack, Akayed Ullah, as he reached for his cellphone.

"These police officers are among the most highly trained police officers in the nation, as are all Port Authority police officers,” said Paul Nunziato, the president of the PAPD’s rank-and-file union. "I am so thankful there was no loss of life and I could not be prouder of our Port Authority police officers, their actions and dedication to their sworn duty."

Nunziato said that Manfredini first heard the commotion and made the call for help. Then, he rushed through waves of terrified straphangers and into the smoke left by the crude explosive’s blast alongside Collins, Preston and Gallagher.

Collins pulled out his service weapon and drew down on the man. Nunziato said when they saw the wires peeking from under his ripped shirt as the man reached for his phone and jumped -- literally -- into action.

"Whether he was trying to other people that could be involved in terrorism or trying to detonate the device, they jumped right on him," Nunziato said.

Nunziato said their split-second decision could have left them dead -- but it was one that potentially stopped the attack from progressing further.

"All four of those officers, if the rest of that device detonated, they would have all been dead," he said. "Along with anyone else who was just trying to get to work."

Two of the officers' neighbors on Monday night described the men as "great guys."

"I'm really not that surprised that he would be involved in saving others and helping others prevent an atrocity from happening in New York City," said Preston's neighbor, Juan Quezada, who added that the officer had a pregnant wife due in a couple months.

Joe Caiati said that Manfriedini, meanwhile, had always wanted to be a cop.

"I think it's great he acted so quickly," he said.

The officers aren’t the only ones who were credited with heroism in the face of what Mayor Bill de Blasio called an attempted act of terror.

MTA station cleaner Sean Monroe said he was just steps behind Ullah when the device went off. But rather than run for his life, he said he helped others get to safety.

"It was a very scary moment but MTA trained me they trained me to do stuff like that so I said, 'Let me help these people,'" he said.