Canadian Prime Minister Stephen Harper on Monday said that the U.S. can't be the only market for his country's energy, including crude from the oil sands of Alberta.

Harper said the decision to delay construction of TransCanada Corp.'s (TRP, TRP.T) proposed Keystone XL pipeline shows the need for Canada to find other markets for energy exports.

"We can't be in a position that our one and only partner can say 'no' to our energy products," Harper said at a Woodrow Wilson International Center for Scholars event. The Keystone pipeline would move Canadian crude to U.S. refineries on the Gulf Coast.

The Keystone project was delayed late last year after pressure from environmental groups mounted. Keystone has become a hot-button topic in the U.S. presidential campaign, with opponents of the Obama administration saying the blocked deal would add jobs and lower gas prices.

Harper said that Canada views the delay as an additional incentive to build the necessary infrastructure to export energy, including crude from the oil sands, to the fast-growing economies in Asia. Even if the Keystone project was restarted this year, he said Canada would not back away from that goal.

Canada's reliance on exporting energy to the U.S. means it receives less for its oil than other countries who deliver to multiple markets, Harper said.

The prime minister also called environmental concerns about oil sands overblown, saying the impact is similar to that of heavy crude the U.S. imports currently from Venezuela.

"When one looks at the other options, oil from the Middle East or Venezuela, the choice should be obvious," he said.

Also at the event, which mainly focused on trade and cross-border issues, Harper said the U.S. should support Canada and Mexico's entry into a proposed free-trade bloc along the Pacific Rim.

In meetings Monday, President Barack Obama spoke "very positively" about Canada's entry into the Trans-Pacific Partnership, Harper said.

"If we're going to build on the North American advantage, it makes sense for all three of the NAFTA partners to be part of the partnership," he said. Harper said the U.S. would benefit from having "like-minded" partners at the negotiating table.

--Tom Fowler and Tom Barkley contributed to this article.