ST. PAUL, Minn. | Police surrounded about 200 protesters Thursday night after a lengthy series of marches and sit-ins timed to coincide with Sen. John McCain's acceptance of the Republican Party's nomination for president.

Caught up in the clash were several reporters assigned to cover the event, including Amy Forliti and Jon Krawczynski of The Associated Press. Officers ordered them to sit on the pavement on a bridge over Interstate 94 and to keep their hands over their heads as they were led away two at a time.

The arrests came three days after AP photographer Matt Rourke, also on assignment covering the protests, was arrested. He was released without being charged Monday after being held for several hours.

The confrontation resulted in about a dozen arrests; protesters had gone ahead with a planned march near the state Capitol even though their permit had expired.

Marchers tried to cross two different bridges leading from the Capitol to the Xcel Energy Center, where McCain was to accept his party's nomination for president. But they were stopped by lines of police in gas masks and riot gear who blocked the bridges after the marching permit expired.

A cat-and-mouse game followed as protesters moved around the Capitol area, splintered, and then organized into a marching force again. The size of the crowd varied from a high of about 1,000 down to a hundred and back to about 500.

About three hours into the standoff, about 300 protesters sat down on a major thoroughfare and police closed the four-lane boulevard. Officers then set off smoke bombs and fired seven percussion grenades, causing protesters to scatter.

A spokesman at an information center set up during the convention said the number of arrests likely would increase as people were processed.

Some of the scattering protesters entered a residential area north of the Capitol. Later, at least three smoke bombs were discharged in the area of apartments and houses.

About two hours into the standoff, police began arresting a handful of people even as the crowd dwindled from about 1,000 to about 100.

"The important thing is even though we didn't have a permit to march, people have decided they want to keep protesting despite all these riot police," said Meredith Aby, a member of the Anti-War Committee.

Even as protesters were being arrested, the mood was much more relaxed than earlier in the week. It even turned festive at times.

Younger people did cartwheels. Tourists came by to check out the spectacle. The chants, which were political at the outset, turned silly a couple hours in.

"You're sexy, you're cute, take off the riot suit," protesters serenaded those blocking their path.

Associated Press writers Amy Forliti and Jon Krawczynski contributed to this report.