Hundreds of protesters from the Occupy D.C. movement marched through downtown to Key Bridge at rush hour Thursday, resulting in a few traffic snarls but no major problems or arrests, police said.

They were among the thousands of supporters of Occupy Wall Street who marked the movement’s two-month anniversary with protests and traffic tie-ups around the country. Occupy protesters vowed to continue agitating for economic justice, even as police in New York and Chicago arrested hundreds and more police departments moved to clear out encampments, citing public health and safety concerns.

In the days since a handful of protesters gathered in Zuccotti Park near Wall Street to speak out against corporate greed and joblessness, the Occupy Wall Street movement has spread to cities throughout the United States and the world. But this week, police moved in to evict the New York demonstrators, sparking outrage and tense confrontations.

Those in New York called for a “Day of Action” on Thursday, with hundreds marching and chanting “shut down Wall Street” at the New York Stock Exchange and during a trek across the Brooklyn Bridge. More than 175 were arrested in New York and at other protest marches in Los Angeles, St. Louis, Houston, Las Vegas and Portland, Ore.

Earlier in the week, some protesters in the District had considered forming a human chain across the Key Bridge, and city officials feared that such a large protest could seriously disrupt the rush hour. Dozens of D.C. police and Arlington County officers were on hand, lined up on the bridge and nearby streets to funnel protesters coming from both sides of the river onto the sidewalks.

Protesters were joined by teachers and other unionized workers for the day’s chilly march near Georgetown in Northwest Washington, one of many such demonstrations planned to call attention to the nation’s crumbling infrastructure. Police shut down K Street NW and then M Street NW as the group of about 300 headed toward the bridge. Tourists and shoppers outside the Sprinkles cupcake shop on M Street gawked and reached for their cameras.

Jarrad Davis, 24, stood on the bridge and said he was marching in support of Occupy camps in Dallas and New York that were evicted this week. He expressed hope that the protesters in the District would be allowed to stay in McPherson Square.

“I hope we can coexist indefinitely,” Davis said.

Local and federal authorities have taken a hands-off posture toward the protesters staying in McPherson Square and Freedom Plaza, despite a Nov. 4 clash with police outside the Washington Convention Center where six were either cited or arrested.

During an interview on NewsChannel 8, D.C. Mayor Vincent C. Gray (D) gave no indication that any preparations were underway to clear the two downtown camps, although he said city officials are monitoring the situation daily.

“People have First Amendment rights, and we want to make sure those rights are observed . . . but our position is that people have to observe the laws of the city and people have to be nonviolent,” Gray said. “To the extent that the folks who are involved in this observe those obvious requirements, we’re certainly willing to work with them. To the extent they don’t, we are going to make sure the laws of the District of Columbia are enforced.”

Since it formed in McPherson Square on Oct. 1, the Occupy D.C. camp has grown into a tent city with portable toilets and food and medical services. U.S. Park Police say that they have seen an “uptick” in crime in the area in recent days, including arrests for assault, drug possession and disorderly conduct. They have not provided exact numbers.

The Downtown DC Business Improvement District has raised concerns about the permanent structures in the square and has allocated extra patrols by sanitation workers to pick up trash. Protesters have said they have their own sanitation committee to pick up trash, and they say some of the petty crime is connected to the city’s chronically homeless population gathering in the square.

Protesters are buying winter tents and other cold-weather gear and hoping to settle in for the long haul.

Matt Johnson, 25, of Southwest Washington predicted that the Occupy movement will continue to expand.

“We don’t have all 99 percent with us yet, but this only started Sept. 17,” Johnson said. “This is just the beginning. We are already talking about an ‘American Spring.’ ”

Staff writers Michael DeBonis, Tim Craig, Allison Klein, Erica Morrison, Robert Samuels and Mary Beth Sheridan contributed to this report.