Police are arresting a couple hundred people who strapped themselves to the White House fence on Sunday to protest the proposed Keystone XL oil pipeline.

The protesters were mostly college students who participated in a peaceful march that began at Georgetown University and ended outside the White House.

They chanted "climate justice now" and carried signs such as "don't tarnish the earth" in their efforts to convince U.S. President Barack Obama to reject the pipeline. They say it will contribute to global warming. Protesters were passionate but quite orderly.

Police were waiting for them with buses and vans to speed the process. The protesters cheered as U.S. Park Police warned them that blocking the sidewalk or strapping themselves to the fence would lead to their arrest.