Police in B.C. are investigating after a gas pipeline was bombed near Dawson Creek, close to the B.C.-Alberta border.

"The explosion damaged but did not rupture the 12-inch-diameter steel gas line and caused a six foot crater in the ground," said a press release on the RCMP website Wednesday morning.

"It appears to have been deliberately set at a point where the pipeline emerged from the ground."

RCMP spokesperson Sgt. Tim Shields told The Canadian Press that police are not characterizing the incident as an act of terrorism, but as an isolated crime.

"Fortunately the gas line didn't rupture when the explosive was detonated but rather it was dented in," said Shields.

"If it had ruptured there would have obviously been a massive explosion and fireball."

The explosion left a 2.5-metre-wide and 2-metre-deep crater in the ground.

The RCMP media release said that police had warned gas and oil companies in the area about a suspicious letter that was sent to local media outlets on Oct. 10. It warned the companies to cease production and leave the area, but did not contain a specific threat.

The damaged pipeline was discovered by a hunter, who noticed a crater at the site on Oct. 12. The crater had not been there when he had hiked by the area the day before, police said.

The targeted pipeline is owned by EnCana and carries sour gas, a form of natural gas that contains hydrogen sulphide, a toxic substance that is removed through a treatment process at the nearby Steep Rock gas plant, the RCMP media release said.

RCMP explosives and forensic experts are investigating, and the Integrated National Security Enforcement Team is also analyzing the letter and the incident.

With files from The Canadian Press