Protesters say they have formed a human chain around the White House to oppose plans for an oil pipeline they say would be bad for the environment.

Thousands of protesters gathered Sunday afternoon and linked hands in a big circle around the presidential residence and buildings on either side of it. They called on President Barack Obama, who was away from the White House at the time, to scrap plans for the pipeline which would carry oil from tar sands in Canada to oil fields in Texas.

The State Department is currently reviewing the pipeline proposal, but Mr. Obama has indicated he will make the final decision.

White House spokesman Clark Stevens said Sunday the president recognizes there are “a number of critical issues” to consider, including climate change, public health and natural resources. But he said the State Department would also consider U.S. energy security and economic issues.

A spokesman for the company behind the pipeline, TransCanada, argued the project would create thousands of jobs and reduce U.S. reliance on overseas oil.