Iraqi security forces moved Saturday to take ground back from anti-government demonstrators in Baghdad, forcing a confrontation that turned violent and filled the streets with careening vehicles rushing the wounded to first aid stations and hospitals.

The melee, which killed six people on Saturday, followed blanket crackdowns in the southern city of Basra on Friday and in the shrine city of Karbala. As the Iraqi government pushed broadly to constrain the protests, it sought in Baghdad, the capital, to restrict them to a smaller public space.

However, with more than 100 people injured, the mounting casualties could make that tactic backfire, and draw back to the streets those protesters who had begun to go home.

“What has been taken by force, we will take back by force,” said Mohammed Juhi, a civil society activist whose organization — I Am Here to Take My Rights — has been on the front line since the demonstrations began in October.