The group demanded that President Barack Obama reject the project, since the “dirty oil” transported through the pipelines would contribute to global warming and lead to possible spills.
Many business and labor groups, however, have expressed support for the pipeline, saying that it would create jobs and constitute a step toward making North America energy independent.
The high-profile demonstration was held as the American Petroleum Institute, the largest lobbying group for the oil industry, is in the process of trying to convince Obama to approve the project, after being rejected twice earlier.
Dozens of activists, including several US environmental leaders, have been arrested at the gate to the White House while protesting against the implementation of a national oil pipeline project.
The 50 demonstrators, including environmental lawyer Robert F Kennedy Jr. and Michael Brune, the executive director of the country’s most influential environmental organization, Sierra Club, held a protest against the Keystone XL project on Wednesday, during which they tied themselves to the White House gate before being taken into custody by the police.
The USD seven-billion pipeline project, which the group were demonstrating against, would carry oil extracted from tar sands in western Canada to refineries along the Texas Gulf Coast, covering a distance of 2,700 kilometers (1,700 miles).