* Environmentalists protest in front of White House
* Oil and gas lobby plans national advertising campaign
WASHINGTON, Feb 13 (Reuters) - Environmentalists and industry groups ramped up efforts on Wednesday to try to sway the White House's decision on the controversial Keystone XL pipeline, a day after U.S. President Barack Obama said he will take action to curb climate-warming emissions.
A small group of activists and celebrities staged a protest in front of the White House to put pressure on Obama to reject the proposed crude oil pipeline. The action came ahead of a rally planned for Sunday on Washington's National Mall, which organizers have dubbed "the largest climate rally in history".
The TransCanada Corp pipeline would link the oil sands of northern Alberta, the world's third largest crude resource, to refineries and ports in Texas. TransCanada has been waiting for approval for 4-1/2 years.
Environmentalists say approval of the pipeline will encourage more development in the oil sands, where extraction is carbon intensive, leading to greater greenhouse gas emissions.
The State Department in the coming days is due to issue a new environmental impact statement on the project, which is expected to guide the White House as it decides whether to give the project the go-ahead.
Canada's Natural Resources Minister said on Wednesday he was cautiously optimistic that Washington would approve the pipeline.
Many environmental organizations welcomed the president's focus on climate change in Tuesday's State of the Union speech. But some warned that the Keystone decision would be more meaningful
"I'm glad to see the president, after the long, odd silence of the campaign, ratcheting up the rhetoric about climate change," said Bill McKibben, founder of environmental group 350.org. "The test of that rhetoric will be what he does about the purest, simplest test: the Keystone XL pipeline."
McKibben, National Association for the Advancement of Colored People President Julian Bond and actress Daryl Hannah were among about 50 people who gathered at the White House.
Meanwhile, the country's biggest oil and gas lobbying group, the American Petroleum Institute, is ramping up pressure on Obama to approve the Keystone project, which its members say will create more jobs and help ensure U.S. energy security.
API plans to launch a national advertising campaign and "grassroots events across the country" on Wednesday, urging Obama to approve the project.
"President Obama must follow through by implementing a national energy policy, lifting existing restrictions in support of responsible development of our vast energy resources, approving the Keystone XL pipeline, and standing up against unnecessary and burdensome regulations," API President Jack Gerard said in response to Obama's speech.
Republican lawmakers, including House Speaker John Boehner, have calling on the president not to delay the decision further.
The House Energy and Commerce Committee launched an online clock this week that tallies how long it has been since the project was first submitted for approval.