A smoking auto in the heart of New York City's teeming Times Square Saturday evening tipped authorities to "an improvised car bomb," officials announced early Sunday morning.

The area was immediately evacuated, with some Broadway shows canceled and streets blocked off. There was no explosion. The device was dismantled and there were no reports of injuries. Officials said the FBI is assisting the New York Police Department in the investigation.

Mayor Michael Bloomberg and Police Commissioner Ray Kelley, attending the White House Correspondents' Association annual dinner in Washington, DC, rushed back to New York while the device was dismantled in the small hours of Sunday morning in a Times Square deserted except for police.

"We avoided what could have been a very deadly event," Bloomberg, still dressed in his formal dinner clothes, told reporters on West 43rd Street across the street from the police Times Square substation. "There were gas cans and bomb making materials in the car."

The car contained three propane tanks, two gas containers, "consumer grade fireworks," clocks and crude wiring, the mayor said.

"This is a further reminder of the dangers we face," he said, reminding residents of the target the city presents to terrorists.

"It certainly could have exploded and caused a pretty big fire and a decent amount of explosive impact," Bloomberg said.

Kelly described a box resembling "gun locker" recovered from the auto and said it was being taken to the Police Department's firing range in the city's Bronx borough to be detonated.

The police "rendered safe an improvised car bomb" in the car found with "its engine running and lights flashing" just off Seventh Avenue, the police commissioner said.

Bloomberg said a T-shirt vendor, identified only as a Vietnam veteran, alerted Police Officer Wayne Rattigan mounted on his horse Megs who checked the car, smelled gunpowder and radioed for help.

The dark green Nissan Pathfinder sports utility vehicle (SUV) near the intersection of West 45th Street and Seventh Avenue, the heart of Times Square, was spotted emitting white smoke, around 6:30 p.m. local time (2330 GMT).

The Fire Department responded and spotted the propane tanks, a spokesman said.

Rattigan ordered that the immediate area be cleared and the area from 44th to 47th Streets along Seventh Avenue evacuated, a Police Department spokesman told Xinhua. Nearby buildings were emptied and the streets cleared of people and vehicles.

The police bomb squad and Emergency Services units were called and when they confirmed the explosive material the cleared area was expanded from 43rd to 48th Streets and from Sixth to Eighth avenues, an enormous area encompassing virtually all of Times Square, in central Manhattan. Traffic in the area came to a near standstill at times.

The mayor said the license plate on the SUV did not match the car and the owner of the plates said they had been on a truck he had sent to a junk yard. Bloomberg said there was no reason to doubt his story but it was being checked out.

"Who abandoned the car and why are under investigation," the mayor said.

The Pathfinder had no vehicle identification number, Kelly said. There were no immediate suspects nor was any group identified as possibly being behind the attempt.

Video surveillance cameras in the area were being checked and the vehicle was believed spotted being driven in the area but no pictures have emerged of any suspect or suspects exiting the vehicle, Bloomberg said, although it would take time to go through surveillance tapes from buildings which were closed over the weekend.

The mayor, who praised Rattigan, the mounted officer, the T-shirt vendor, the police and fire departments and other city agencies and New Yorkers in general for helping avert a disaster. He was flanked by New York State Governor David Paterson, and other city officials.

Officials said police were held over to check their facilities for suspicious devices and a Xinhua reporter heard dispatchers on police radios instruct "all commands" to check the vicinity of police stations and vehicles for possible devices. They also were alerted to check suspicious vehicles for possible devices.

Asked by reporters what New Yorkers should do, Bloomberg advised them to go about their business as usual and to continue enjoying the balmy weather, but quickly added, "If you see something; say something," as the T-shirt vendor did.