Canada's Natural Resources Minister Joe Oliver says the government does not consider its move to co-operate with the U.S. to reduce greenhouse gas emissions as an environmental concession.

Oliver made the comments following a recent CBC News report that the government was willing to accept targets to advance the Keystone pipeline project.

"We don't regard the proposed policies as concessions," Oliver said after a meeting with U.S. Energy Secretary Ernest Moniz in Washington, D.C.

"It has been our objective to continue to make progress on environmental enhancement for two reasons. One, because we have a responsibility as global citizens and two because we need to have the social licence to continue to develop our resources," he said.

CBC News reported last week that Prime Minister Stephen Harper recently wrote a letter to U.S. President Barack Obama formally proposing "joint action to reduce greenhouse gas emissions in the oil and gas sector" in order to advance the Keystone pipeline project.

Sources told CBC News the prime minister is willing to accept targets proposed by the United States for reducing the climate-changing emissions and is prepared to work in concert with Obama to provide whatever political cover he needs to approve the Keystone extension.

Harper and Obama met on the sidelines of the G20 summit in St. Petersburg, Russia, on Friday, but Obama's attention is focused on Syria. The White House has yet to respond to Harper's letter.

Oliver said he wouldn't comment on the "purported" letter or communications between the two leaders. But he did say that  "Canada wants to work with the U.S. administration on a wide range of environmental and energy issues, including collaborative efforts to reduce greenhouse gas emissions from the development of North American conventional and non-conventional oil and gas reserves."

Speaking on CBC News Network's Power & Politics, Oliver told host Evan Solomon that a carbon tax is not on the table. "We didn't talk about a carbon tax and we're not going to and the United States isn’t contemplating that at all," he said. 

Oliver said earlier in the day that he presented the strengths of the Keystone XL project to Moniz.

The U.S. energy secretary's department isn't the one responsible for approving TransCanada Corp.'s Keystone XL pipeline that would connect Alberta's oilsands to Texas refineries, but it does have input.