A six-car pileup on Route 58 westbound at the Wilroy Road exit Thursday afternoon increased to nine involved vehicles during the aftermath, a city spokeswoman said.

The initial accident happened at 5:09 p.m. and involved six vehicles. City spokeswoman Diana Klink described it in a news release as minor.

When a Suffolk Police unit was responding at 5:25 p.m. to help fellow officers, a van struck the cruiser from the rear and then struck an 18-wheeler, Klink said.

The involved officer was not injured. Two others were transported to Sentara Obici Hospital for injuries that were considered minor.

The roadway was closed briefly while the vehicles were moved to the emergency lane, Klink said. The cause is under investigation.