BOSTON -- Two MBTA Green Line trolley trains collided Thursday morning near the Boylston Street T station, transit police said.

Nine minor injuries were reported with some passengers complaining of neck and back pain. They were taken to the hospital. Two of those saying they were injured were train operators and one was a Green Line official who happened to be on one of the trains.

"We had, primarily, individuals who had, for the most part, minor injuries," Boston EMS technician Tim Holland said.

The crash happened about 8 a.m. and MBTA officials said one trolley rear-ended another. One of the cars became derailed upon impact. Crews were working to get it back on track and service was supended between Kenmore Square and Park Street station while the scene was cleared. Passengers were bused between those stations.

Outside, ambulances lined the sidewalk and passengers left the station in a hurry.

"I just saw people coming out, kind of nervous, walking away, and people hurt," Noel Torres said.

One woman said her friend was on the trains that collided.

"She just called and said there was a train accident, the train seems like it's off the tracks. She fell on the train and she's in a lot of pain," Maria O'Toole said.

Another woman said she works with her sister at 10 Park Plaza downtown and couldn't find her.

"I drive in and she takes the Green Line in," Susan Locigno said, saying her sister didn't show up at the office.

It is unclear what caused the accident and MBTA officials were continuing to investigate.