PORTLAND, Ore. - Members of Sen. Barack Obama's presidential campaign have apologized for an incident that occurred at his recent campaign rally at Portland's Tom McCall Waterfront Park.

Following the May 18 rally, the Portland Police Bureau was made aware that several portable toilets had been placed in the center of the police memorial at the park.

A number of officers complained it was in poor taste and dishonored those that the memorial is dedicated to.

After being notified of the incident, Obama campaign officials sent an apology letter to Portland Police Chief Rosie Sizer, and the Portland Police Association, calling it an unintentional error.