Police are calling a second explosion on a northern pipeline an act of terrorism.

The blast happened on an EnCana natural gas line near Dawson Creek in northeastern B.C. and the RCMP's national terrorism unit is investigating.

Two electricians working on the line noticed the aftermath of the explosion on Thursday morning. The pipe was damage but not ruptured.

The latest incident is only 20 km from a blast along an oil pipeline that happened this past weekend.

The RCMP is investigating a link between the two explosions and a warning letter mailed out to area media outlets.

"We're looking at any and all evidence that would have been left at the scene," said Sgt. Tim Shields. "We're comparing it, of course, to the first incident that occurred only about four days ago and, of course, we are going under the assumption that both explosions are linked and this was a direct attack, It was targeted against the infrastructure of B.C. and we are taking this very seriously."

EnCana owns both the pipelines and is trying to calm rattled nerves in the neighbouring communities.

"What's important is that we want to ensure the public, the people that live in this area, that we are doing everything we can to ensure their safety," said Alan Boras, EnCana spokesperson.

Employees are being told to watch for anything suspicious in the area and call RCMP if they notice anything out of the ordinary.