Cindy Sheehan and other peace activists plan to "die symbolically" for the next four days outside the White House to represent the American soldiers who have died in Iraq.
Sheehan, whose son Casey died in Iraq last year, organized the vigil as the U.S. military death toll in the war neared 2,000.
She said she hoped 2,000 people would attend the vigil throughout the week to represent each American death. Each participant was to receive a wrist bracelet with the name of a fallen soldier.
Sheehan brought attention to the anti-war effort last summer by camping outside President George W. Bush's ranch in Crawford, Texas. She was arrested outside the White House in a protest last month.
Sheehan also said she would visit Arlington National Ceremony, Walter Reed Hospital and the Iraqi Embassy this week, AP reports.