(CNN) -- A gunman was at large after firefighters and police responded to a reported shooting Friday at a high-rise building in Orlando, Florida, authorities said.

Authorities received a report shortly before noon of a shooting on an upper floor of the high rise, said John Tormos of the Orlando Fire Department.

A spokesman for the Orange County Sheriff's Office, which is helping the city police department, said investigators are looking for a man wearing a blue Polo shirt, gray vest and blue jeans.

"We're in a search mode for the gunman," said Jim Solomons, a spokesman for the sheriff's office.

CNN affiliate WESH reported that at least eight people were shot at the Gateway Center -- a 16-story building near Lake Ivanhoe and Interstate 4.

WESH reported that the interstate was closed in both directions near the office building.

Police cars and emergency vehicles surrounded the area, video showed. It also showed people fleeing.

This is so upsetting.