The New York Times reported Shahzad appeared before a magistrate for less than 10 minutes. He didn't enter a plea to the five felony counts against him and answered simply "yes" when Magistrate Judge James C. Francis IV asked whether an affidavit about his finances was accurate.
Francis appointed federal defender Julia Gatto to represent Shahzad and granted a prosecution request that he be held without bail. The judge set the suspect's next hearing for June 1.
Shahzad, who was then handcuffed and led away, is charged with one count each of attempting terrorism by attempting to kill people; attempted use of a weapon of mass destruction; using a destructive device in an attempted crime of violence; transporting explosives; and attempting to destroy property with fire and explosives.
Shahzad allegedly planned to target four other high-profile sites besides New York's Times Square, police allege.
Shahzad allegedly told investigators he also planned to attack Rockefeller Center, Grand Central terminal, the world financial center across from Ground Zero and Sikorsky, the Connecticut defense contractor, WNYW-TV, New York, reported Tuesday.
Shahzad is charged in a May 1 incident in which a smoking sport utility vehicle was found packed with explosives in Times Square but did not detonate.
Michael Balboni, a former homeland security adviser for New York state, said picking numerous locations for attack guarantees maximum exposure and publicity.
"So they want to pick things that are iconic that perhaps have a lot of people so they can increase the body count," Balboni said. "Anything to make it as dramatic as possible."