ELIZABETH -- A Union County police officer directing traffic in front of the county prosecutor's office Wednesday was struck by a driver who had a suspended license and was carrying a handgun in his car, authorities said.

The officer, whose name was not released, was at a routine traffic post on Rahway Avenue at Elizabethtown Plaza about 4:45 p.m. when he was struck by man a driving west on Rahway Avenue.

Authorities said the officer suffered back injuries that were described as minor. He was taken by ambulance to a health care facility for treatment and later released, officials said.

County Public Safety Director Andrew Moran said the driver, Aberto Rosario, 21, of Linden, was driving on a suspended license, and was in a car with a suspended registration. Rosario told police that he did not see the officer before the collision occurred, Moran said

He said police also found a handgun in the car.

Rosario received multiple motor vehicle summons and was charged with illegal possession of a weapon. He was being held last night at the Union County jail on $100,000 bail.

The collision occurred directly in front of the Union County Prosecutor's Office and less than 70 yards from the Union County Administration Building and the Union County jail, both of which are on Elizabethtown Plaza.

The back of the county courthouse is also Elizabethtown Plaza, as is the courthouse annex and the county parking garages.

An officer directs traffic on Rahway Avenue at Elizabethtown Avenue each afternoon.

Police closed off usually heavily traveled Rahway Avenue at Broad Street for about an hour after the collision.

Tom Haydon may be reached at thaydon@njadvancemedia.com. Follow him on Twitter @Tom_HaydonSL. Find NJ.com on Facebook.