"El Bahnasawy, who has been in custody since he was arrested by the FBI in May 2016, pleaded guilty to terrorism offenses and is awaiting sentencing."
Haroon and Salic had been arrested in foreign countries by foreign authorities in connection with these charges and it was "the hope and expectation" they would be extradited, the department said.
The department said the trio had been communicating through Internet messaging apps.
"These three men allegedly plotted to conduct bombings and shootings in heavily populated areas of New York City during the Islamic holy month of Ramadhan in 2016, all in the name of ISIS (the NYC Attacks).
"El Bahnasawy purchased bomb-making materials and helped secure a cabin within driving distance of New York City to use for building the explosive devices and staging the NYC attacks.
"Haroon allegedly made plans to travel from Pakistan to New York City to join El Bahnasawy in carrying out the attacks, and travelled within Pakistan to meet with explosives experts in furtherance of the plot.
"And as El Bahnasawy and Haroon prepared to execute the NYC Attacks, Salic allegedly wired money from the Philippines to the United States to help fund the terrorist operation."
Investigators said the aim was to target concerts and injure as many people as possible.
On May 12 last year, the department said, El Bahnasawy sent the undercover officer an image of Times Square and stated: "[W]e seriously need a car bomb at times square. . Look at these crowds of people!"
The same day, El Bahnasawy also expressed his desire to "shoot up concerts cuz they kill a lot of people."
El Bahnasawy described the plan to attack concerts as follows: "[W]e just walk in with guns in our hands. That's how the Paris guys did it."
WNBC said the suspect in custody allegedly spoke to the other men about also wanting to strike Times Square and subways during rush hour.
Investigators told WNBC the goal was to maim as many people as possible.
The alleged plot was uncovered months ago but details were not released until today, WNBC said, because the search continued for other possible terror connections.
"The FBI and the Joint Terrorism Task Force, they're going to work with the US Attorney's office to make sure that this is not just idle talk," former FBI Supervisor JJ Klaver told WNBC. "They are going to look at the extent of the plans being made and the extent that these guys are taking actions to further those plans.
"The most challenging and difficult decisions that are made in these investigations is finding where the balance is - between protecting the integrity of the investigation and letting the public know the vital information they need to determine whether or not they feel safe foing to a particular venue," Klaver said.
Sources familiar with the case said this was not a sting operation, but the FBI and NYPD got onto the lead suspect early on. Some of the suspect's list of targets mirror past plots.