Philadelphia, 6:45 EDT--Dozens of demonstrators wearing black clothes and masked with black bandanas have moved into the streets in front of City Hall, trying to disrupt the GOP convention by blocking the buses carrying demonstrators.
Crowds have been gathering in the city center for more than an hour. Waves of cops tried to clear the street, only to have anarchists begin lying down on the pavement in front of vehicles.
After a tense standoff, the pitch of the crowd is beginning to tip toward pandemonium. Protesters are banging drums and blowing whistles, dancing and chanting, stopping all traffic.
Cops have been forced to turn private traffic around, rather than clear the way.