An Iraq-based Iranian opposition group that is fixated on conspiracy theories allegedly carried out attacks in Iran and elsewhere for decades, but now relies on a different weapon: the press release.

The United Nations mission here, which has been attempting to facilitate the exit of some 3,400 members of the opposition People's Mujahedeen Organisation of Iran (PMOI) from Iraq, where they have been based for decades, has been the latest target of the group's statement-issuing ire.

Iraq wants the PMOI out of its territory, and signed an agreement with the UN in December to that end.

On February 18, the first group of 397 exiles moved from their longtime base of Camp Ashraf in Diyala province northeast of Baghdad to Camp Liberty, a former US military base near the Iraqi capital, as part of that process.

But soon after, the group began complaining about conditions in Camp Liberty and accusing the United Nations Assistance Mission for Iraq (UNAMI), which in January said Liberty met "international humanitarian standards," of misrepresenting conditions there.

The PMOI's focus on public relations campaigns marked by frequent statements to the media and cultivating well-known western politicians to speak on its behalf differs dramatically from its past activities.

The leftwing group was founded in the 1960s to oppose the shah of Iran, but took up arms against the country's new clerical rulers after the 1979 Islamic revolution.

The US State Department, which blacklists the PMOI as a terrorist organisation, says it has carried out attacks that killed Iranians, as well as American soldiers and civilians, from the 1970s into 2001.

Now-executed Iraqi dictator Saddam Hussein allowed the PMOI to establish Camp Ashraf in Iraq after he launched the 1980-88 war with Iran in which the group reportedly fought alongside his forces, and provided financial backing to the group.

But the PMOI said it renounced violence in 2001 and its members in Iraq were disarmed following the 2003 US-led invasion, leaving it in need of other tactics.

It successfully campaigned to be delisted as a terrorist organisation in Europe and is working to do the same in the US too.

A day after the first group of the exiles moved to Liberty, PMOI spokesman Shahriar Kia sent a statement by email alleging a UN expert who assessed the camp told "lies" and apparently "was compelled to file an unrealistic report," with "necessary modifications" made by "political authorities" from UNAMI.

"The bungalows and toilet facilities" were "dirty and unusable," and "there is serious water shortage and electricity is cut off, as in prisons, after 10.30 pm."

A statement emailed the next day described Camp Liberty as "a highly controlled prison," referring to the presence of Iraqi security forces.

Iraqi forces carried out two deadly raids on Camp Ashraf in 2009 and 2011, leaving dozens of people dead.

It continued: "Everything shows that at the behest of the Iranian regime, the Iraqi government has turned this camp into a prison and regretfully, UNAMI and (UN envoy) Mr Martin Kobler himself ... assist in this prison-making by confirming it as a refugee camp."

Another email from Kia on February 27 referred to the "lies that Martin Kobler made to the residents of Camp Ashraf for a forcible relocation to Camp Liberty."

When asked about the PMOI statements, Kobler told AFP that Camp Liberty "was host of 5,000 American soldiers, so it should be possible to have the infrastructure ready also for these 400 persons who are now living there."

"I do not think that the infrastructure problem is the problem," he said.

"If there is garbage, the garbage can be removed and should be removed, and the government of Iraq stands ready ... to have garbage trucks available, but they have to enter the camp to remove the garbage," he said.

"The aim of the whole exercise is to have the ... refugee status determination moving," he said, referring to a process which must be completed before the exiles can be resettled.

The PMOI meanwhile says it is facing "conspiracies."

"The whole plan for the relocation of the residents of Camp Ashraf to Camp Liberty is an Iranian plan, and the mullahs regimes plan, and nobody else," Kia said in an interview with AFP, referring to the cleric-led government in Tehran.

He referred to the new camp as "Prison Liberty," saying that "their plan is to destroy the Iranian opposition" there.

Kia also said that "espionage cameras and ... eavesdropping devices" in Liberty give information "to the Iranian embassy and to the agents of the Iranian regime."

When asked about the purpose of the flurry of statements on the UN, Kia referred to demands over Camp Liberty.

These include the removal of Iraqi armed forces from Liberty and freedom of movement for residents, but also, despite numerous statements accusing the UN of lying about conditions there, a demand for around-the-clock UN monitoring.