Graham: Hold NYC Terrorist Under 'Law of War,' Do Not Read Him Miranda Rights

ISIS Message Two Weeks Ago Warned About 'Christmas in New York'

Four police officers with the Port Authority of New York and New Jersey who were first on-scene after a man partially detonated a bomb in a commuter passageway stopped him as he fumbled with his cell phone.

Officers Sean Gallagher, Drew Preston, Jack Collins and Anthony Manfredini rushed to the area where Bangladeshi immigrant Akayed Ullah was on the ground injured after attempting to set off an improvised explosive device, investigators said.

A loud explosion rocked the busy pedestrian passageway connecting the Port Authority Bus Terminal with New York City's IND and IRT subway lines around 7:20 a.m. Monday. 

A throng of commuters reportedly alerted Manfredini, 28, to the bombing, and the retired Marine, who also worked as a bomb technician, rushed toward the blast site.

The four officers spotted Ullah injured on the floor - with wires sticking out of his clothing - but fumbling with his cell phone, and feared he could have been trying to use it as a detonator to create another explosion, according to police.

Manfredini radioed to his colleagues, who responded to the scene.

Gallagher, 26, and Preston, 36, are also veterans, with Preston having served three tours in Iraq, according to the New York Post. Collins, 45, is a practicing attorney, the paper said.

A source told the Post the cops acted quickly to secure the phone and place Ullah under arrest before he could gravely harm any commuters.

PANYNJ Chairman Kevin O'Toole thanked the officers for their bravery, saying that their fast response assured "there were no serious injuries and [the terminal] was secured without further incident."

The Port Authority Bus Terminal is the busiest bus hub in the world, serving New Jersey and Pennsylvania commuter buses as well as nationwide Greyhound service and long-haul buses to Canada.

The authority also operates the region's three major airports, as well as all tolled bi-state crossings from the George Washington Bridge southward.

After the bombing, the MTA subway agency ordered trains to skip the 42nd Street-Port Authority station as the police continued their investigation.

Service was restored for the afternoon rush, the Port Authority said.

Gorka: Stop Looking at Your Cell Phone, Have a Plan in Case Terror Strikes

ISIS-Inspired Bomber Sets Off Device on Subway Platform Near Times Square; 3 Injured