Police presence was nearly invisible until a small group of pro regime extremists began singing and chanting. At that point police officers moved in to separate the two groups, and the square was swarmed by Jordanian riot police, or darak, who took up a horseshoe formation between them.
At one point there was a scuffle among the protesters, as a group of young men confronted the police. The darak stood, impassive, as hundreds of young men angrily shouted a refrain from the regional Arab uprisings, a line not heard in Jordan before this week: "The people want the fall of the regime."
The anger quickly subsided as protest leaders on a nearby truck drew the crowd back to chanting slightly less confrontational slogans: "Freedom is from God, whether you like or not, Abdullah," participants shouted.
Protests in the cities of Irbid and Mafraq saw similar minor confrontations at protests, according to Police Department Spokesman Mohammad Al Khatib, but they, too, were stopped without injuries or arrests.
Many young activists say they will pursue further demonstrations tonight, near Jordan's Interior Ministry, an area that has seen several clashes between groups of young protesters and police over the past few days. Protests are also planned in other cities throughout the country tonight, according to some opposition leaders, meaning violence could still commence as night falls.
In one hopeful sign, Mr. Hamarneh says some protest leaders would not participate in any demonstrations today in an effort to avoid violence.
"I think it was just a flareup, a spontaneous reaction, and not the way Jordanians usually conduct themselves," says Nimer Al-Assaf, the deputy secretary general of the Islamic Action Front, Jordan's largest opposition party. "I think, in general, people are sane, and will listen to the voices of reason, and will stop doing things like that."