Several thousand anti-war demonstrators have marched through Washington.
Some were dressed as doves of peace and others waved signs with anti-war messages.
Much larger protests had been planned for this weekend to oppose policies of the World Bank and the International Monetary Fund.
But the financial meetings were cancelled after the September 11th terrorist attacks and the protesters' anti-globalisation cause was transformed into a call for peace.
The protests were mainly peaceful, but police in riot gear used pepper spray on demonstrators at least once during a morning march led by an anarchist group. Police arrested some protesters at the skirmish, says a police spokeswoman, but she couldn't provide more details.
In another incident, District of Columbia Assistant Police Chief Terrance Gainer was sprayed in the face with something that brought him to his knees.
Two officers helped him behind police barricades and he later returned to work.
Many protesters had cancelled their trip to Washington after the attacks, but some groups just shifted to an anti-war theme.
"The nation's in grief. I'm in grief. But adding more victims to the list is not going to do anyone any good," said Ms Gill Smith, a 63-year-old demonstrator from New Jersey.
AP