At least 15 people were killed in clashes following a mortar attack on an Iranian dissident camp north of the Iraqi capital Baghdad on Sunday, two security sources said.
It was not immediately clear who fired the mortars early on Sunday.
The fifteen people died in later confrontations between security forces and camp residents, the two sources said.
One of the sources said Iraqi security forces had opened fire on a crowd which had stormed a post at the entrance to the camp. Around 50 people were wounded, the source said.
The Mujahadin-e-Khalq (MEK) dissident group said 34 of its members in the camp had been killed by Iraqi security forces. Some of them were machine-gunned with their hands tied behind their backs, MEK said in an emailed statement.
MEK calls for the overthrow of Iran's clerical leaders and fought alongside the forces of former Iraqi Sunni Muslim dictator Saddam Hussein in the Iran-Iraq war in the 1980s.
It has been seeking to recast itself as an Iranian opposition force but is no longer welcome in Iraq under the Shi'ite Muslim-led government that came to power after U.S.-led forces invaded and toppled Saddam in 2003.