Secretary of State Hillary Clinton said Thursday that the U.S. government remains committed to making a decision by the end of the year on a controversial oil pipeline that TransCanada Corp. (TRP, TRP.T) wants to build between Canada and the Gulf Coast.

Speaking in the U.S. after a meeting with Canadian Foreign Affairs Minister John Baird, Clinton said the State Department would release an environmental review of the Keystone XL pipeline this month and then decide whether to approve the 1,700-mile pipeline project by the end of the year.

The State Department had already announced its intentions to stick to that timeline.

"We've been clear from the beginning that the safety of the pipeline is one of our highest priorities," Clinton said.

The State Department is examining whether the pipeline serves the best interests of the U.S.

Environmental groups are opposed to the Keystone XL pipeline. They object to the type of crude oil that would be transported through the line and have raised questions about the oil's ability to corrode the pipeline.

Supporters say the pipeline would supply oil to the U.S. at a time when global supplies have been disrupted.