A man who appears to be Shahzad vowed in the video that he would strike the U.S. to avenge the deaths of Muslims killed by American forces.
Al-Arabiya broadcast excerpts of the 40-minute video Wednesday. The station did not say how it got hold of the video, which it said was released by the Pakistani Taliban. NBC News has decided not to air the video at this time because of concerns about its authenticity.
In the video excerpts, Shahzad is sitting on the ground in a black turban and military fatigues, with a gun next to him as he recites verses from the Quran.
He says he will carry out a "revenge attack" against the U.S. to avenge the deaths of Muslims killed in Afghanistan and Pakistan by the U.S., and that he hopes his actions will touch the hearts of Muslims.
Al-Arabiya said the full tape shows Shahzad meeting with a prominent Pakistani Taliban figure, Faqir Mohammed, the deputy leader of Tehrik-e-Taliban Pakistan, along the Afghan border.
Shahzad was arrested days after the failed May 1 bombing in Times Square.
He pleaded guilty in June to carrying out the attack, and admitted to attempting to establish contact with the Taliban while on a trip to Pakistan. He also told the New York court that he considers himself "a Muslim soldier."
He said he sought and received five days' training in explosives before returning to the United States in February to carry out the bomb plot with funding from the militant group.
The indictment said he received $5,000 in cash on Feb. 25 from an unnamed coconspirator in Pakistan and $7,000 more on April 10, sent at the coconspirator's direction.