A highway ramp near the Pentagon was shut down for hours Monday night while authorities investigated what they said appeared to be a suspicious package.

They said it was determined shortly before midnight, about three hours into the incident, that no explosive or suspicious device was involved.

Virginia state police said the item was in a vehicle that had been backing up the southbound Interstate 395 ramp to Washington Boulevard. A trooper stopped the vehicle about 8:30 p.m. and a handgun was found inside along with “a suspicious looking package,” the police said.

State police bomb technicians and the Arlington County fire department went to the scene to investigate the package, which was on the front passenger seat, a police spokeswoman said.

At about 12:30 a.m. Tuesday police said the ramp would be reopened soon.

Police said in a statement that the driver of the vehicle had been taken into custody.

The incident occurred southwest of the Pentagon and near the U.S. Air Force Memorial and the southern edge of Arlington Cemetery.

Arlington authorities said Washington Boulevard was closed between Columbia Pike and Route 110.

Details of why the package aroused suspicion could not be immediately learned.