Authorities were investigating a possible explosive threat from a suspicious vehicle at the gate of Picatinny Arsenal base Friday.

Update: 6 p.m.: No explosive threat was ultimately found in a vehicle that approached Picatinny Arsenal Friday.

ROCKAWAY TOWNSHIP -- A possible explosive threat at the entrance of Picatinny Arsenal prompted the evacuation of employees from the base Friday.

At about 11:30 a.m., a driver tried to gain access to Picatinny Arsenal through the post's truck gate when security personnel noticed something suspicious within the vehicle, Picatinny Arsenal spokesman Ed Lopez said.

The driver was being detained and questioned Friday, he said.

Authorities were treating the situation as if it was an explosive threat, and the installation was coordinating with local, state and federal agencies, Lopez said.

Employees were instructed to leave the post at 1:44 p.m., he said.

While some business in the area of the base had reportedly been evacuated, a spokesman for the Rockaway Townsquare mall said it remained open. The mall had been contacted by authorities about the possibility it would need to close, but never did, he said.

Mount Hope Delicatessen located near the base still had people inside Friday afternoon. Bill Lasapio, whose son owns the deli, said a customer was having lunch there when he received a message from the base saying he couldn't return to work.

John Kozlowski, of Rockaway Township, said he was glad authorities had someone in custody.

"Picatinny is one place you don't want to screw around with," he said.

For most of the afternoon, Route 15 between Route 80 and Berkshire Valley Road was closed. Authorities announced it had reopened shortly before 5 p.m.

Heavy delays remained through the area.

INCIDENT AT PICATINNY ARSENAL CLOSES TRUCK GATEPICATINNY ARSENAL, N.J. – At approximately 11:30 a.m., a driver tried... Posted by Picatinny Arsenal on Friday, April 17, 2015

Ben Horowitz and Louis C. Hochman contributed to this report.

Justin Zaremba may be reached at jzaremba@njadvancemedia.com. Follow him on Twitter @JustinZarembaNJ. Find NJ.com on Facebook.