The US government said Thursday it would study an alternate route for a controversial US-Canada oil pipeline, and pushed back its final decision on the project until 2013 -- after next year's presidential elections.
The move, a temporary victory for environmentalists against the multi-billion-dollar Keystone XL project, is based on concerns over how the pipeline would affect an area in the state of Nebraska, the State Department said in a statement.
Critics had expressed concern about preservation of the Sand Hills area, which has "a high concentration of wetlands of special concern, a sensitive ecosystem, and extensive areas of very shallow groundwater," it said.
"Given the concentration of concerns regarding the environmental sensitivities of the current proposed route through the Sand Hills area of Nebraska, the Department has determined it needs to undertake an in-depth assessment of potential alternative routes in Nebraska," it said.
The State Department has been holding public consultations on plans to build the 1,700-mile (2,700-kilometer) Keystone XL pipeline from the tar sands of Canada's Alberta province to the Gulf of Mexico in the southern United States.
The route proposed by TransCanada would pass through the US states of Montana, South Dakota, Nebraska, Kansas and Oklahoma before ending up at refineries in Texas.
In its long-awaited environmental impact statement on the project, the State Department said in August that the pipeline would be safer than most current oil transportation systems.
But many environmentalists fear a potential pipeline accident would spell disaster for aquifers in central US Great Plains states. That could disproportionately endanger rural towns and Native Americans, they say.
A number of environmental and citizen groups are also fighting the pipeline because exploiting the unconventional oil sands of Alberta requires energy that produces a large volume of greenhouse gasses.
The State Department, which is handling public consultations as the pipeline would run across the border with Canada, had initially expected to issue its final decision by year's end.
But it had already cautioned last week that it might miss the deadline.
On Thursday, the department said it was "reasonable to expect" that its review process "could be completed as early as the first quarter of 2013."
US President Barack Obama said in a statement that he supported the State Department's decision to "seek additional information" before deciding whether to give the green light to the plan.
"Because this permit decision could affect the health and safety of the American people as well as the environment... we should take the time to ensure that all questions are properly addressed and all the potential impacts are properly understood," Obama said in a statement.
Explore further: Weird weather lingers in Alaska's largest city