A white van without license plates parked in the heart of Times Square caused a security scare Wednesday that rattled New Yorkers and thousands of holiday tourists milling about amid preparations for the city's massive New Year's Eve celebration.

Just weeks after a police-involved shooting in the area, the NYPD blocked off part of Times Square for about two hours starting at 11 a.m., calling in counterterrorism and bomb squads after officers noticed the 1992 Dodge van, which had a bogus law enforcement placard in the windshield, parked on Broadway between 41st and 42nd streets.

Two high-rise buildings, home to Nasdaq and publishing company Conde Nast, were partially evacuated, but occupants were allowed back in around 1 p.m.

Stephanie Gonzalez, who works in the glass-covered tower directly in front of where the van was parked, said announcements were made around 11 a.m. that people in the building should head to its west side, away from the vehicle. She left the building entirely.

"Post-9/11, you're just not going to stick around to figure it out," she said.

There were no corresponding terrorism threats involving the vehicle, said chief NYPD spokesman Paul J. Browne. No explosive devices were found in the van, and the area was reopened to traffic about two hours after patrol officers spotted the van.

But police take extra care around New Year's Eve when the celebration draws hundreds of thousands of revelers from around the world to the heart of Times Square to see the ball drop at midnight. Squads routinely patrol for suspicious vehicles and do sweeps in garages before the event.

"Its presence in Times Square just before New Year's Eve causes us concern, and that's why we're taking extra precautions," Browne said.

Hours after the scare, Mayor Michael Bloomberg stood outside the Nasdaq building, down the street from where the van had been parked, and declared the city safe for the New Year's Eve festivities.

"Somebody thought it was suspicious. They called. We checked it out. It turned out not to be anything bad," he said. "We take every threat or every potential threat seriously."

Nasdaq said its trading was unaffected. Conde Nast was in the process of evacuating when the order was lifted. But the scene shook those who live and work nearby.

Stephen Radner, an attorney who works on the 40th floor of the same tower, said the announcements to move to the west side of the building caused confusion.

"I couldn't quite understand it," he said. "If there was an explosion, it would have shattered everything in the building."

The van was parked in a row of cars beneath some of the large billboards that ring the square.