BAGHDAD (AP) — Anti-government protesters say at least 15 people have suffered stab wounds in Baghdad’s Tahrir Square, the epicenter of their movement, after political parties and Iran-backed militia groups briefly joined them, raising fears of infiltration by authorities.

Lawmakers convened a parliament session Thursday to amend laws governing compensation to include victims of military operations, according to the session agenda seen by The Associated Press.

There were over a dozen knife attacks by the late afternoon when protesters aligned with political parties and Iran-backed militias withdrew from Tahrir, three demonstrators and a witness said. There were no fatalities.

Another protester who requested anonymity said the attacks, “might have been perpetrated by the parties or someone who wants to ignite problems with the parties.”

Iraqi officials have repeatedly warned of infiltrators within the peaceful protesters seeking to coopt the movement.