New York Governor Andrew Cuomo says the suspect may have crafted the device from online instructions, and so far it doesn't appear to be part of a larger plot.
"We're going to keep being New Yorkers". Ferdous said Ullah last traveled to Bangladesh's capital Dhaka - where he was born and raised - in September, but police had no information on why he was there.
He said he had been motivated by United States air strikes on IS targets in Syria and elsewhere, the New York Times reports.
Tourists visiting New York City as well as commuters all said that they felt safe in the city even after the pipe bombing at the Port Authority bus terminal.
"This is a major hub in Manhattan, nearly every major subway goes through or near here, and it was in the subway tunnels that the suspect set off this explosive device", she said.
The NYC Taxi and Limousine Commission confirms to NPR's Joel Rose that Ullah held a for-hire vehicle driver's license from March 2012 through March 2015, meaning he could have driven a black auto or livery vehicle in the city during that span.
He lived in the same apartment building as his brother whom he recently worked with at an electrical company close to Port Authority, police said.
"Today, four courageous Port Authority police officers risked their lives confronting an armed terrorist to protect others from harm", Port Authority Police Benevolent Association President Paul Nunziato said in a statement.
He added that there are "no additional known incidents at this time" and "there are no additional known activities".
While the suspect was seriously wounded in the blast, injuries to the three victims were described as "non-life-threatening". "Everybody was scared and running and shouting". "A woman fell. And nobody even went to stop and help her because the panic was so scary", she said. Some subway train lines were evacuated following the explosion. Police shut down the entire block and there was a heavy police presence outside the home. NY in December sees a surge of visitors who come to see elaborate store displays, the Rockefeller Center Christmas tree and Broadway shows. The Port Authority bus terminal was temporarily closed and later reopened, although Greyhound and airport service remained suspended. Buskers and other entertainers at entrances to the tunnel often draw crowds.
S&P 500 index emini futures dipped in the moments after the initial reports of an explosion, but major stock indexes later opened slightly higher.
The last terror attack to rock NY was on October 31, when another ISIS-inspired man drove a rented truck onto a bike path near the World Trade Center, killing eight people.
Police initially said the suspect was the only person injured when the device detonated.