Footage (released by the PMOI) shows Iraqi riot police using batons
Seven Iranian dissidents have been killed during a raid by Iraqi security forces on their camp north of Baghdad, Iraqi police have said.
Eyewitnesses say Iraqi police have surrounded the People's Mujahideen of Iran (PMOI) camp and clashes are continuing inside.
Iran wants the camp closed. The exiles fear they will be forcibly repatriated.
The US gave the camp some protection until it handed security control back to Iraq earlier this year.
The PMOI said Iraqi riot police stormed the camp using batons and live fire on Tuesday.
Amnesty International said it was "seriously concerned" about the incident, and had seen footage which "clearly showed" Iraqi forces beating people repeatedly.
There are contradictory reports coming out of Ashraf about what sparked the violence.
The PMOI released images showing alleged protests at the camp
Police say residents of the camp fired teargas at them but the PMOI says it was the police who fired the tear gas.
An Iraqi official told AFP news agency more than 50 Iranians had been arrested.
Iraqi officials said they were trying to establish a police post in the camp, north of Baghdad.
"It is our territory and our right to enter, to impose Iraqi law on everybody," a defence ministry spokesman told al-Arabiya television.
The PMOI set up a base in Iraq in the 1980s.
The exiles' presence was welcomed by then-President Saddam Hussein, who was fighting a war against Iran at the time.
The camp was disarmed by US soldiers following the US-led invasion of Iraq in 2003.
But since then relations between Iran and Iraq have improved and the Iraqi government has repeatedly vowed to close the camp.
Iraqi forces took over its security from the US earlier this year, and the top US general in Iraq said he had received no advance warning of the raid.
A US official said the Iraqi government had given assurances that residents of the camp would not be forcibly transferred.
Iraqi government spokesman Ali al-Dabbagh said Iraq would "not force the Iranians to depart against their wishes".
"But they should co-operate with governmental procedures," he said, according to the Associated Press.
The PMOI released video of what it said were Iraqi forces using tear gas and water cannon, and pictures showing residents it said had been injured.
The group is considered a terrorist group by the US and Iran. It was removed from an EU terrorist list earlier this year after a legal battle.
But reports suggest Washington has received intelligence from the group, and has urged Iraqi authorities not to repatriate its members or use lethal force against them.
"We have had promises from the government of Iraq that they would deal with the [PMOI] in a humane fashion," said US Gen Ray Odierno.
A PMOI spokesman said residents were terrified of being handed over to Iranian authorities.
The group says it is ready to return to Iran - but only on condition that none of its members will be prosecuted or persecuted.