CANNES, France - Prime Minister Stephen Harper says his American counterpart remains "noncommittal" to a multi-billion-dollar pipeline plan but hasn't made any decision against the project.

U.S. President Barack Obama rattled the Keystone XL's Canadian supporters with comments earlier this week to a TV station in Omaha.

Obama, who is heading into an election year, said environmental issues would weigh just as heavily in government deliberations about the project as job creation and energy security.

Harper, asked about Obama's musings on the environment following a G20 summit in France, said he was well aware of the president's remarks.

"I thought on balance they were noncommittal and he indicated he had yet to make a decision, and we respect that," said Harper.

Harper had called the massive, $7 billion project a "complete no-brainer" in September but gave a more diplomatic, muted endorsement Friday.

"It's a project that not only will create a vast number of jobs in both our countries but is essential to American energy security," said the prime minister.

"My view on the project hasn't changed; President Obama has to make a decision."

Reading the U.S. tea leaves has become a nerve-rattling parlour game for the pipeline's proponents.

"Folks in Nebraska like all across the country aren't going to say to themselves, 'We'll take a few thousand jobs if it means our kids are potentially drinking water that would damage their health,"' Obama said earlier this week, speaking to KETV from the White House. "We don't want, for example, aquifers to be adversely affected. Folks in Nebraska obviously would be directly impacted."

Changing the route of the 2,700-kilometre pipeline has been called a potential project-killer by TransCanada Corp., of Calgary.

The pipeline is supposed to deliver 700,000 barrels a day of crude oil from the Alberta oil sands to refineries on the Gulf of Mexico. It will pass through Montana, South Dakota, Nebraska, Kansas, Oklahoma and Texas.

Obama's warning wasn't the only recent splash of cold water on the project.

U.S. State Department spokeswoman Victoria Nuland said earlier this week the year-end deadline for completing their pipeline project review is not set in stone.

"We'd like to get it done by the end of the year, but if thoroughness demands a little more time nobody has slammed the door on that," Nuland said. "Our first obligation to the American people, to the president, is to ensure that we do this in a rigorous, transparent and thorough way."

Her comments came just after TransCanada warned that delay by regulators could threaten the entire project.

The company responded to the State Department hedging by issuing yet another statement, saying it expects the Obama administration to keep its previous commitment to decide on the pipeline before the New Year.

"The Department of State announced last spring it targeted a decision on a presidential permit by year end. We remain focused on that commitment," said TransCanada spokesman Terry Cunha.