WASHINGTON - The U.S. State Department says TransCanada's proposed Keystone XL pipeline poses no major risks to the environment and will not spur further oilsands production in Alberta, moving the controversial project one step further to a final decision by the Obama administration.

Insisting repeatedly that its long-awaited assessment was "not a rubberstamp," the department's Kerri-Ann Jones said Friday there's no evidence the pipeline will significantly impact the six U.S. states in its path as it carries crude from northern Alberta to Gulf Coast refineries in Texas.

"This is not the rubberstamp for this project," said Jones, disputing several big American environmental groups who immediately decried it as such.

"The permit that is required for this project has not been approved or rejected at all ... it should not be seen as a lean in any direction either for or against this pipeline. We are in a state of neutrality."

Canadian officials intend to continue to develop technologies that will lessen the greenhouse gas emissions associated with oilsands production, according to the analysis.

"We are working closely with them," Jones told a conference call in the U.S. capital. "We closely follow what's going on in terms of international regulations in this area."

She added that oilsands production will continue with or without the Keystone XL pipeline.

The Obama administration now has 90 days to determine whether the controversial project is in the national interest of the United States. In that determination, Jones said, State Department officials will consider the environmental assessment as well as the economic impact of the pipeline and "foreign policy concerns."

The outcome wasn't a surprise to the American environmental movement, for whom opposition to the pipeline has become a passionate rallying cry in the aftermath of failed climate change legislation last year.

Leading environmentalists say the State Department has refused to fully assess the risks.

The Natural Resources Defense Council accused the State Department of failing to study pipeline safety measures or examine alternate routes that would avoid the Ogallala aquifer in Nebraska, a crucial source of water in the state.

In fact, the State Department report said TransCanada needed to conduct more study, and possibly add more anti-spill precautions, around the aquifer.

Jones add that alternative routes had also been studied.

"We feel that the proposed route of the applicant is the preferred route ... alternative routes were either worse or similar," she said.

The NRDC's Susan Casey-Lefkowitz expressed dismay at the State Department's assessment in a statement.

"It is utterly beyond me how the administration can claim the pipeline will have 'no significant impacts' if they haven't bothered to do in-depth studies around the issues of contention," she said.

"The public has made their concerns clear and the administration seems to have ignored them. If permitted, the proposed Keystone XL tarsands pipeline will be a dirty legacy that will haunt President Obama and Secretary Clinton for years to come."

Jim Lyon, senior vice-president of the National Wildlife Federation, said the analysis was "strike 3 for the State Department" after two "failed rounds" of environmental review and warned of legal woes ahead.

"The document still fails to address the key concerns for landowners and wildlife," he said. "It is almost certain to be scrutinized in other venues, including a probable legal challenge. This only escalates the controversy in a process that is far from over."

The State Department analysis comes as anti-pipeline activists continue a two-week civil disobedience campaign outside the White House.

More than 300 people, including Canadian actress Margot Kidder, have been arrested as they try to convince U.S. President Barack Obama to block the pipeline. As many as 54 more were arrested on Friday.

Environmental activists say Keystone XL is a disaster waiting to happen, pointing to several recent spills along pipelines, and are opposed to Alberta's oilsands due to the high levels of greenhouse gas emissions involved in their production.

Proponents, meantime, say the pipeline will create thousands of jobs and help end U.S. reliance on Middle Eastern oil.

TransCanada president Russ Girling welcomed the State Department report.

"Support for Keystone XL continues to grow because the public, opinion leaders and elected officials can see the clear benefits that this pipeline will deliver to Americans," he said in a news release.

"The fundamental issue is energy security. Through the Keystone system, the U.S. can secure access to a stable and reliable supply of oil from Canada where we protect human rights and the environment, or it can import more higher-priced oil from nations who do not share America's interests or values."