U.S. Senate leaders supporting the Keystone XL oil pipeline from Canada said they're confident their northern neighbors are good stewards of the environment.

U.S. Sens. John Hoeven, R-N.D., and Joe Manchin, D-W. Va., who authored a bill in support of the Keystone XL oil pipeline, met in Washington with Canadian Ambassador to the United States Gary Doer to discuss the project.

Hoeven said that, with more than 30 oil pipelines already crossing the U.S.-Canadian border, Canada has shown it's a responsible energy partner.

"Canada is committed to developing the oil sands with good environmental stewardship, and already has a strong record of achievement," he said.

Pipeline planner TransCanada was forced to revise the planned route for Keystone XL through Nebraska to avoid a drinking water aquifer. A Nebraska court recently sanctioned the state governor's role in the revision, clearing the path for federal review of the pipeline.

Opponents of Keystone XL, submitted for U.S. approval more than six years ago, point to a legacy of releases from the existing Keystone pipeline and worry the production of Canadian crude oil may be more carbon-intensive than other forms.

A State Department review of the pipeline found some of the environmental issues would be prevalent with or without Keystone XL.

"Companies like Exxon and Shell are working with their Canadian counterparts to develop new technologies to reduce greenhouse gas emissions as they increase production to help both Canada and the U.S. to become more economically strong and energy secure in an increasingly volatile world," Hoeven said in a statement Thursday.

The bill backed by Hoeven and Manchin would do away with the federal permitting processes necessary for Keystone XL. President Barack Obama said he'd veto any legislation that would undermine the vetting procedures.