NEW YORK — Police found an "amateurish" but potentially powerful bomb that apparently began to detonate but did not explode in a smoking sport utility vehicle in Times Square, authorities said Sunday.
Thousands of tourists were cleared from the streets for 10 hours after a T-shirt vendor alerted police to the suspicious vehicle, which contained three propane tanks, fireworks, two filled 5-gallon gasoline containers, and two clocks with batteries, electrical wire and other components, Police Commissioner Raymond Kelly said.
"We avoided what we could have been a very deadly event," Mayor Michael Bloomberg said. "It certainly could have exploded and had a pretty big fire and a decent amount of explosive impact."
The bomb appeared to be starting to detonate but malfunctioned, top police spokesman Paul Browne said Sunday.
Firefighters who arrived shortly after the first call heard a popping sound, said Fire Commissioner Sal Cassano, who described the sound as not quite an explosion.
"I think the intent was to cause a significant ball of fire," Kelly said.
No suspects were in custody, though Kelly said a surveillance video showed the car driving west on 45th Street before it parked between Seventh and Eighth avenues. Police were looking for more video from office buildings that weren't open at the time.
Homeland Security Secretary Janet Napolitano said on NBC's "Meet the Press" that officials are treating the incident as a potential terrorist attack. The mayor said earlier Sunday, "We have no idea who did this or why" but said it's not surprising the city is a frequent target of terrorism.
"These things invariably ... come back to New York," Bloomberg said.
The SUV was towed early Sunday to a forensic lab in Queens, where it was being "thoroughly checked for prints, hairs and fibers," Browne said Sunday. Napolitano said fingerprints had been recovered from the vehicle.
The T-shirt vendor alerted police at about 6:30 p.m., the height of dinner hour before theatergoers head to Saturday night shows.
Smoke was coming from the back of the dark-colored Pathfinder, its hazard lights were on and "it was just sitting there," said Rallis Gialaboukis, 37, another vendor who has hawked his wares for 20 years across the street.
A white robotic police arm broke windows of the sports utility vehicle to remove any explosive materials. A Connecticut license plate on the vehicle did not match up, Bloomberg said. Police interviewed the Connecticut car owner, who told them he had sent the plates to a nearby junkyard, Bloomberg said.
Heavily armed police and emergency vehicles shut down the city's busiest streets, choked with taxis and people on one of the first summer-like days of the year. Times Square lies about four traffic-choked miles north of where terrorists bombed the World Trade Center in 1993, then laid waste to it on Sept. 11, 2001.
The car was parked on one of the prime blocks for Broadway shows, with seven theaters housing such big shows as "The Lion King" and "Billy Elliot."
The curtain at "God of Carnage" and "Red" opened a half-hour later than usual, but the shows were not canceled, said spokesman Adrian Bryan-Brown.
Bloomberg left early from the White House correspondent's dinner Saturday night. President Barack Obama, who attended the annual gala, praised the quick response by the New York Police Department, White House spokesman Nick Shapiro said.
He has also directed his homeland security and counterterrorism adviser, John Brennan, to advise New York officials that the federal government is prepared to provide support.
Brennan and others will keep Obama up to date on the investigation, Shapiro said.
Contributing to this report were AP Washington bureau chief Ron Fournier, AP Radio correspondent Julie Walker in New York and Associated Press writers Eileen Sullivan and Pete Yost in Washington, Michael Kuchwara in New York and Robert H. Reid in Kabul.