Earlier today the National Park Service clarified where Occupy Wall Street protesters may assemble on the steps of Federal Hall: an exclusive "First Amendment Rights Area" on the right side of the stairs. But for a few hours today it seemed the feds and NYPD were about to forcibly remove everyone at Federal Hall. At 6:24 p.m., Ryan Devereaux Tweeted, "Financial District locked down w/ #ows on the steps of Federal Hall. 'They're about to all be arrested,' says a cop."

OWS had been sleeping on Wall Street last week, but after police blocked that action, they began assembling on the steps of Federal Hall, which is under the jurisdiction of the National Park Service. The NYPD and the Park police soon barricaded the protesters into an area on one half of the steps, and today officially dubbed it the "First Amendment Rights Area." Late this afternoon, Park police handed out one copy of the rules of the steps, listed in a document five pages long. Protester Amelia H.M. Tweeted a photograph of the new rules on the steps—"Here's the gold. On demonstrations & "1st Amndmnt Area" max. 75ppl" and also noted "At 6 pm a new rule at Federal Hall prevents noise over 60 decibels. What does that sound like, you say? Normal conversation. #sleepOWS #OWS"

According to the rules, if there are more than 25 protesters on the steps, they require a permit, or face arrest. So the protesters are now working it like a nightclub at capacity, by having one protester enter the "Free Speech Cage" whenever one exits. Protester Max Braverman told us, "We're the most exclusive nightclub in NYC"— Here's a livestream—and that's why there currently seem to be more protesters outside of the barricades watching the protesters who remain on the steps:

Free live streaming by Ustream

Nick Pinto says, "First arrests as NYPD barricade sidewalk. A woman calls out "you're all heroes!" #OWS" John Del Signore is at the scene and says some streets around Federal Hall are shut down, except to the press and residents. The Wall Street entrance is still open; barricades are up, but as of 6:45 everyone is allowed through at William and Wall.

The National Park Service police are on the steps, counting the protesters to make sure they don't exceed 25. And, for your history, Federal Hall is where the First Congress met and wrote the Bill of Rights.