Police in both Nassau and Suffolk counties said there was no credible terror threat to Long Island Tuesday night in the wake of a deadly attack in Manhattan near the World Trade Center — but they were taking precautions anyway.

The commissioners of both police departments said they weren't taking any chances and urged residents to remain vigilant. Patrick Ryder, of Nassau, and Tim Sini, of Suffolk, both said they were remaining in constant contact with the FBI and other law enforcement agencies.

In Nassau, police also intensified patrols and deployed officers in tactical gear.

"It's much more likely that a civilian, a regular resident, will prevent a terrorist attack than a law enforcement officer," Sini said. "That's our job — to run down the leads. But don't be afraid to come forward because you're not sure what it is. When in doubt, send it to us." 

Still, both acknowledged that a lone wolf attack like the one on Halloween in Manhattan, without the telltale signs like an arsenal of weapons or collection bomb-making materials, can be difficult to detect.

"This is the type of attack you can't really plan for," Ryder said. "You hope you can prevent more than plan."

Part of that prevention comes in the form of large cement barriers Nassau recently received a grant for that will block vehicles from plowing into large crowds.