Officials investigate leak in Alberta pipeline

CALGARY, Alberta (AP) - Canada's oil and gas regulator says it is investigating a leak in a TransCanada natural gas pipeline in a remote corner of Alberta.

National Energy Board spokeswoman Rebecca Taylor said Thursday that the TransCanada had a rupture on its NOVA gas transmission line. She says the pipeline has been shut down.

TransCanada spokesman Shawn Howard says no public safety threat was expected. He says the line carries sweet gas, which is low in poisonous hydrogen sulfide.

Canadian Prime Minister Stephen Harper has been pushing for U.S. State Department approval of the Keystone XL pipeline. That pipeline would carry oil from Canada's tar sands to the U.S. Gulf Coast.

Environmental groups oppose the pipeline saying it would carry "dirty oil" that contributes to global warming. They also worry about a spill.