Canada

Photo: The Canadian Press. All rights reserved.

Robert F. Kennedy Jr. is arrested in Washington, Wednesday, Feb. 13, 2013, as prominent environmental leaders tied themselves to the White House gate to protest the Keystone XL oil pipeline. (AP Photo/Ann Heisenfelt)

Several leading American environmentalists were among dozens of people arrested outside the White House on Wednesday as they protested TransCanada's proposed Keystone XL pipeline, a flashpoint for the U.S. climate change movement.

After 48 activists gathered outside the White House's northernmost wrought-iron fence, along a stretch of Pennsylvania Avenue where protests are prohibited, police began their methodical arrests as supporters chanted: "Hey, Obama, we don't want no climate drama."

Among those arrested were Michael Brune, the executive director of the Sierra Club; James E. Hansen, a prominent climate scientist; Bill McKibben, a vocal anti-Keystone XL activist; and environmental lawyer Robert F. Kennedy Jr.

Brune is the first Sierra Club leader in the organization's 120-year history to be arrested in an act of civil disobedience after the Sierra Club suspended its longtime policy against the practice due to Keystone XL.

Civil rights activist Julian Bond and actress Daryl Hannah, who was arrested in August 2011 at a similar anti-Keystone protest outside the White House, were also apprehended during the peaceful protest.

Some of the protesters had tied themselves to the fence on a grey, drizzly day while others simply refused to move when police repeatedly asked them to vacate the sidewalk.

The protest came the day after U.S. President Barack Obama delivered his fourth State of the Union address. While he reiterated his call for swift action to combat climate change, Obama made no mention specifically of Keystone XL.