Tens of thousands of people dressed in white are marching through the Scottish city of Edinburgh pressing for action against African poverty at next week's Group of Eight summit at the nearby Gleneagles resort.
The demonstrators plan to form a human chain around the medieval city.
What organizers are calling the "Make Poverty History" march and rally is timed to coincide with the Live 8 rock concerts being held around the world.
The demonstrators want the industrial nations to cancel African debt, increase aid to poor nations and remove trade barriers blocking the import of African products.
Road barricades are in place and shop windows in downtown Edinburgh have been boarded up for fear of violence. Two thousand police officers are on hand to keep order.
Leaders of the world's seven principal industrial countries Britain, Canada, France, Germany, Italy, Japan and the United States and Russia open the summit Wednesday.
Information for this report is provided by AP, AFP and Reuters.