The NSA's controversial surveillance programs are being credited with helping to stop two separate terror plots in New York City, government officials testified on Tuesday.

Sean Joyce, Deputy Director of the Federal Bureau of Investigation, testified before a congressional committee that the telephone record review process led to the discovery of “a nascent plotting” to bomb the New York Stock Exchange.

Officials also said that email, telephone and businesses records tracked by the NSA helped investigators learn of a plot by Najibullah Zazi Adis Medunjanin and others to attack the city’s subway system.

A top NSA official said the program has helped prevent more than 50 possible terror attacks since September 11.