The Saint John Police are investigating a suspicious death that happened at the Saint John Regional Hospital. (Connell Smith/CBC)

Saint John Police are releasing few details about a suspicious death that occurred over night Tuesday at the Saint John Regional Hospital.

Sgt. Glenn Hayward told CBC News police were called to the hospital at 12:20 a.m.

The major crime unit is investigating, he said.

Hayward declined to divulge the victim's gender or age.

He also declined to reveal whether anyone is in custody in connection with the death.

"At this time, due to rules of evidence and procedural fairness, no other information can be divulged," Hayward said.

Sonya Green-Haché, the spokeswoman for the Horizon Health Network, said only that it's a police matter.

There is no impact on hospital operations or on the ability of the public to visit the hospital, she said.

Hospital staff told CBC News they've been told not to speak to the media.

Some patients said it appears to be business as usual inside the hospital. However, there are some doors in the hospital that are usually open that are now closed, including the amphitheatre, located on the main level.

"I was coming out of my pre-op and two orderlies were walking up the hall and it was near where the amphitheatre is and there's a great big sign on the amphitheatre door saying it was closed," said Tracy Scott.

"I don't know if they were talking about that door, but they said 'I'm surprised they don't have RCMP officers at that door' and I didn't understand what they were talking about."

At least five police vehicles were at the hospital Wednesday morning, including a forensic van.

Two vehicles were parked by the emergency entrance, while the other three were at the back of the building.