Update (6:55 p.m. EST): Thousands of continue to stream across the bridge at a slow pace, keeping on the sidewalk. Meanwhile, The New York Times brings word that Brandon Watts, the protester who police arrested in a dramatic Zuccotti Park raid earlier has been charged with larceny and attempted assault.

Update (6:36 p.m.): These little moments do remind one of the truly pressing issues in life (via David Horvitz Twitter):

Update (6:30 p.m.): Protesters have walked onto the pedestrian walkway on the Brooklyn Bridge, reports Breaking911. Meanwhile, The New York Times reported that 60 people had been arrested at the entrance to the bridge, then it tweeted that "scores more" had been taken into custody by police.

Update (6:17 p.m. EST): New York City Councilman Jumaane Williams has reportedly been arrested, along with "dozens of union members after they sat on the ground on Centre Street," according to The New York Daily News.

Update (6:14 p.m. EST): Arrests are starting on the Brooklyn Bridge, beginning with a union president, per Ed Schultz:

Update (6:09 p.m. EST): A march is departing Foley Square for the Brooklyn Bridge. Earlier reports said 100 officers had massed there. Probably more by now. Live feed narrator Tim Pool says the rumor is police are standing shoulder-to-shoulder on the bridge.

Update (5:46 p.m. EST): CBS has a live feed going from its helicopter. We grabbed a screenshot:

Update (5:43 p.m. EST): Turns out the airspace is not closed. NBC tweets its pilot misunderstood directions from the control tower and was not actually ordered out of the area.

Update (5:37 p.m. EST): Occupy Wall Street estimates 10,000 people in Foley Square. The march from Union Square just arrived and the narrator said, "easily 10,000, probably more." Several unions are on hand, and people are massing across the street outside the square, unable to enter because it's too crowded. Meanwhile, NBC New York reports police have closed the airspace over the protest and told its chopper to move on.

Update (5:27 p.m. EST): Throwing back to Thursday morning, the New York Observer sends along this photo it posted earlier Thursday of Ray Lewis, the retired Philadelphia Police captain, in flexi-cuffs. That there is a sight you don't see every day:

Update (4:50 p.m. EST): The march has started moving and is making its way toward Foley Square, where many more protesters are reportedly gathering. Breaking911 tweets: "2,000+ Protesters on Greenwich Ave & 6av Southbound in the Street Against Traffic." Meanwhile, Allison Kilkenny tweets that the Foley Square subway station has been closed. The live feed reports the square is already full of people, and this Twitter photo from Allison Rae seems to support that:

Update (4:40 p.m. EST): Mayor Michael Bloomberg and Police Commissioner Ray Kelly had a press conference Thursday afternoon at Bellevue Hospital and gave some specific information on the day's events so far. The Village Voice has a good summary:

Kelly reported that there had been 177 arrests today, five for assault. Seven police officers were injured; five had liquid thrown on them and one had a hand injury. Kelly described the incident in which the officer's hand was injured at Zuccotti. He said that there was an attempt to arrest people who had moved barriers, and during that situation an object was thrown at the officer. Kelly added that the officers had been released from the hospital. Bloomberg put the estimated number of protesters at less than 1000, saying that it was "hard to tell." "Rest assured that the NYPD is trained for these situations," he said. "If you're here in the city and you want to protest, you can."

Update (4:36 p.m. EST): Protest or no, the game must go on. These chess enthusiasts in Union Square didn't care they were in the middle of a gigantic political rally (via Thomas Macmillan on Twitter):