Officials declined to elaborate, but the New York Times said the case involved the arrest of a man planning to build and detonate a bomb in New York with government workers as the target.
More details are emerging:
The person told The Associated Press that the 27-year-old man was acting as a lone wolf and was taken into custody Saturday. He allegedly was inspired by al-Qaida, although his citizenship was not immediately known.
A news conference by the mayor, police commissioner, and Manhattan district attorney was scheduled for Sunday evening.