The fight over a proposed pipeline to transport crude oil from Canada to Gulf Coast refineries is picking up again as groups urge President Barack Obama to either approve or reject the pipeline.

The American Petroleum Institute held a conference call with reporters Thursday to emphasize the virtues of the Keystone XL pipeline that TransCanada wants to build.

API is the oil and gas industry's main lobbying group, and spokesman Marty Durbin says Obama should approve the pipeline as soon as possible to boost the economy.

But environmental groups plan a protest outside the White House on Sunday. They want Obama to reject the pipeline because they worry that it could contaminate water supplies, increase air pollution around refineries and harm wildlife.