Speaking after the U.S. State Department released a final environmental impact statement on the controversial pipeline, Oliver said U.S. President Barack Obama now had all the facts to be able to decide.

"This has been a lengthy and thorough review process. The benefits to the United States and Canada are clear. We await a timely decision on this project," Oliver said.

Oliver described the environmental review, which said the Keystone XL pipeline would be unlikely to increase the pace of Canadian oil sands development, as a "positive step on the route to approval".

(Reporting by Alastair Sharp and Nia Williams; Editing by Nick Zieminski)