A law enforcement source told CBS News senior investigative producer Pat Milton police are looking at a possible suicide bomber but the situation is fluid.
White House Press Secretary Sarah Sanders said that President Trump had been briefed on the incident.
People reported seeing the bomb squad responding to the incident and posted images of the scene on social media.
The explosion has led to delays along some of the subway lines that pass beneath the bus terminal. Many subway lines were forced to bypass the area.
New Yorkers were advised to avoid the area.