Police said the organizers of the march had refused to cooperate with them by obtaining a parade permit and informing the department about the intended route of Thursday's march.
"The Portland Police Bureau is asking that downtown Portland businesses be aware of this event and that they prepare for possible disruptions," the department said in a written statement. "Additionally, the Police Bureau is asking for the community's patience and understanding as there may be disruptions to vehicle, pedestrian and TriMet traffic in the downtown core during the duration of the event."
Police said Occupy Portland had sent them a letter stating that on advise of counsel, they would not be seeking a parade permit despite police contentions a well-planned parade has greater success.
The Portland march is part of a ripple effect from recent rallies in Lower Manhattan protesting what are seen as excesses by corporate and financial executives at a time when the U.S. middle class is mired in high unemployment and stagnant wages.
College students and nurses said Wednesday they were throwing their support behind the Occupy Boston movement.
CNN said hundreds of nurses with the Massachusetts Nurses Association were expected to join local college students and other Occupy Boston protesters to demand U.S. social and economic policy change.
Organizers have said they are inspired by the Arab Spring revolutions in Africa and the Middle East, The Boston Globe reported.
In New York, the Amalgamated Transit Union and United Federation of Teachers said they supported the Occupy Wall Street activists. "The ATU applauds the Occupy Wall Street activists for their courage and strength to expose the greed and corruption on Wall Street as the rest of America struggles to survive," Larry Hanley, ATU International president, said Tuesday in a statement.