SEATTLE —  Recent anti-war marches like those in San Francisco and New York featured the usual demonstrators, signs and chants, but now, fearing their message isn't being heard, war protesters are planning more aggressive action that they say will be hard to ignore.

"People will step up their actions, there will be active civil disobedience," Simona Sharoni of United for Peace in Thurston County, Wash., told Fox News earlier this week.

Activists from Direct Action, a San Francisco anti-war group, have been making their own battle plan should there be war in Iraq. Representatives say they will shut down 70 targets in San Francisco alone, including power plants, water systems, the Federal Reserve, oil companies and the Pacific Exchange and TransAmerica building.

And their hit list goes beyond economic targets. Some protesters are promising to chain themselves to fences at schools and day care centers so working parents will have to stay home from their jobs, giving them the chance, organizers say, to contemplate how war affects the children of Iraq.

San Francisco activist Leone Reinbold helped organize the WTO protest in Seattle three years ago. She blames the violence and damage on anarchists from the radical fringe, not mainstream demonstrators.

All the same, police departments from coast to coast know keeping things peaceful won't be easy.

"We know based on the last one that each preceding demonstration has been a little bit more volatile than the one before," said San Francisco Deputy Police Chief Greg Suhr.

Some protesters are vowing to bring traffic to a standstill as they recently did on a Seattle bridge. But many wonder if paralyzing the morning commute and other disruptions will win converts or make enemies of people losing patience with their tactics.

Fox News' Dan Springer contributed to this report.