Had the bomber chosen the right kind of fertilizer, the bomb would have had the force of more than 100 pounds of TNT. But instead of ammonium nitrate, the kind of fertilizer used by Oklahoma City bomber Timothy McVeigh, the bomber used a harmless fertilizer, New York City Police Department spokesman Paul Browne said.
The license plate on the car was apparently stolen from an auto repair shop outside Bridgeport, Conn., according to law enforcement officials.
The authorities told ABC News that the previous owner provided a description of the man who bought the car, and told investigators the vehicle was sold for several hundred dollars in cash, with no written records identifying the purchaser.
The license plate found on the Pathfinder also came from Connecticut, #98CY09, according to photographs of the vehicle.
The surrounding area was evacuated after street vendor Duane Jackson saw smoke coming from the Pathfinder and alerted police. Jackson, who has been working in Times Square for 13 years, said he is always on alert in the crowded public space, and in touch with police. "Vigilance is the key," said Jackson. "Keep your wits about you [and] don't take anything for granted."
Police moved back thousands of theatergoers and tourists as the bomb squad moved in.
Technicians blew open the back doors and trunk and found the car packed with propane canisters and gasoline containers.
"Clearly it was the intent of whoever did this to cause mayhem," said New York police commissioner Ray Kelly.
But the detonator, alarm clocks hooked up to fire crackers, failed to work.
"They would not have been able to have stopped the bomb if it had been wired properly," said former counterterrorism czar Richard Clarke, now an ABC News consultant. "Someone was able to drive into New York with what looks like bomb parts, drive right into the heart of Times Square, pull up on the sidewalk, jump up and run away and not get caught."
The bomb bore similarities to two Al Qaeda-connected attacks on a London nightclub and an airport in Scotland in 2007. Three vehicles used in the attempted bombings contained propane gas tanks.
Al Qaeda has posted videos showing how to construct a bomb using propane tanks and gasoline.
On Sunday night, the Taliban released a video featuring Hakimullah Mehsud, who U.S. and Pakistani authorities had thought was killed in a drone strike in January.
On the recording Mehsud can be heard saying, "The time is very near when our fedayeen will attack the American states in their major cities." He also claims that Taliban fedayeen "have penetrated the terrorist America, we will give extremely painful blows to the fanatic America."
Mehsud's video was recorded April 4, and Mehsud threatens attacks in the days and weeks to come.
Earlier, in the hours after the failed Times Square bombing, a Taliban group in Pakistan claimed responsibility for what it called a "jaw-breaking blow to Satan's USA.
But U.S. officials expressed doubt about a Taliban connection.
Mayor Bloomberg said that so far there was "no legitimate evidence" the Taliban or al Qaeda were involved. "There's one group of the Taliban that claims credit for everything, including traffic jams," said Bloomberg.