In the history of Iraq’s fragmented and dysfunctional parliament, brawls are not uncommon. The Iraqi House of Representatives is well known for its fiery debate, sometimes leading to fist fights between members.

But the latest row in Iraq’s chaotic legislature is about more than the usual political mudslinging.

Twenty-five years after the end of the Iran-Iraq war, which had no clear winner, the Iraqi parliament found itself last week confronted with the ghosts of the bloody conflict that cost millions in casualties and billions of dollars in damage to both countries.

Parliament was suspended 22 August indefinitely after rival lawmakers from the Shia National Alliance scuffled with members of the Sunni Iraqiya List objecting to posters depicting Iranian leaders appearing in Baghdad and other Iraqi cities.

The scuffle started after Haidar Al-Mulla of the Iraqiya bloc requested that the issue of the public display of images of late Ayatollah Rohallah Khomeini and Iran’s current supreme leader, Ali Khamenei, in Iraqi cities be put to debate in parliament.

In a statement, Al-Mulla said hanging pictures of top Iranian clerics and leaders in street corners and police and army checkpoints was “an encroachment upon Iraqi sovereignty”.

“Displaying pictures of foreign leaders, in any country, needs justification because it is unacceptable under any circumstance. It’s particularly so in Iraq, given that it fought with Iran in a fierce war, and some of the pictures are provocative,” Al-Mulla said.

Al-Mulla reminded parliament that Shia politicians blasted Sunnis who raised pictures of Turkish Prime Minister Recep Tayyip Erdogan during sit-ins held earlier this year in protest against the Shia-led government.

Even before Al-Mulla wrapped up his speech Shia members protested his intervention and demanded that he should be stopped. Soon, lawmakers from the Shia alliance approached Al-Mulla and other Iraqiya members and a confrontation erupted.

Then lawmakers from both sides pushed and wrestled each other, forcing parliament Speaker Osama Al-Nujaifi, a Sunni politician and one of Iraqiya’s leaders, to adjourn the session. Snapshots, apparently taken by MPs mobile phones, showed the assembly erupting in chaos as both sides exchanged shouts and blame.

Inevitably, the heated row moved soon outside the parliament’s meeting hall, signalling another proxy war among Iraq’s two rival Muslim sects already entangled in a bloody sectarian power struggle.

Leader of the Shia National Iraqi Alliance, Ibrahim Al-Jaafari, accused Al-Mulla of being “ignorant” of the high status of the Iranian leaders, whom he described as “Muslim [religious] authorities”.

Al-Mulla “has failed to realise that these figures constitute an authority to their followers, regardless of their nationalities”, he said.

He wondered why pictures of “icons such as [Indian preeminent leader Mahatma] Gandhi and [Bolivian revolutionary Che] Guevara” are being raised and adorned worldwide while Iraqi Shias are denied the right to “show respect to their supreme authorities”.

Al-Jaafari, who described Al-Mulla’s remarks as “braying”, insisted that the Iraqiya lawmaker should apologise because his speech violated the sanctity of Shia religious leaders.

“These dignitaries mirror the consciousness of the umma [Islamic nation] and he [Al-Mulla] should have paid due respect to their names,” Al-Jaafari said.

He blamed Al-Nujaifi for allowing Al-Mulla to air the complaints in the first place.

Some Shia MPs said they would be seeking to remove Al-Nujaifi from his post.

Outside parliament some Shias demanded that Al-Mulla be “hanged” for transgression. They accused him of being a former loyalist of Saddam Hussein and that he worked for his security apparatus. The local government in Basra, Iraq’s southern port city, which Al-Mulla represents, decided to blacklist him.

On the other hand, the Iraqiya bloc came to the defence of Al-Mulla. Its spokeswoman, Maysoon Al-Damaluji, said Al-Mulla’s statement was in line with normal parliamentary procedures and practices.

“We have received the approval of the presidential office to raise this subject,” she said at a press conference.

“Instead of having a civilised discussion over the controversial issue, the debate turned into a fist-fight,” she said. “These pictures provoke the feelings of Iraqi citizens and violate Iraq’s sovereignty,” she added.

Sheikh Samir Fouad, a top cleric in the Sunni-dominated city of Samarra, accused those who are behind the posters as being “unfaithful” to Iraq.

“We tell all those who do not have allegiance to Iraq that they belong to a country that doesn’t wish Iraq well,” he told worshipers during Friday prayers.

Iraq’s parliament is not in short supply of disputes. It rarely meets and often fails to ratify laws or oversee government business. Many Iraqis consider its members as mostly corrupt and incompetent.

But this parliamentary crisis came amid spiralling violence that has raised new fears that Iraq is returning to the bloody sectarian violence that nearly tore the country apart in 2006 and 2007.

A series of terrorist attacks have rocked Baghdad and other Iraqi cities and killed nearly 5,000 civilians and wounded 12,000 others since the beginning of 2013, according to the United Nations Assistance Mission for Iraq.

The explosions, car bombings and machinegun attacks targeted mostly cities and neighbourhoods of Iraqi Shia majority. In recent weeks, the security forces have carried out a series of operations in Sunni areas around Baghdad as part of a campaign the government is calling “the revenge of the martyrs.”

Numerous reported attacks on Sunni mosques or cafes frequented by Sunnis, and a series of beheadings of Shia families in sectarian mixed areas, including children, in recent weeks have raised fears of tit-for-tat sectarian killings.

On such a level, the spat over the appearance of the Iranian leaders’ images in Iraqi cities is risking adding fuel to the fire.

Khomeini and Khamenei’s posters first started to appear after the United States pulled its troops from Iraq in December 2011. But a massive display of the images appeared in Shia neighbourhoods and cities across Iraq in early August, as part of an Iranian-sponsored annual “Day of Jerusalem”, in solidarity with the Palestinians.

Many of the images remained in place since then.

Pictures of other Iranian senior clergy, such as Ayatollah Mahmoud Hashemi Shahroudi and Ayatollah Khazim Hairi, also adorn walls and in many Baghdad streets. Both clerics, who were close to Prime Minister Nuri Al-Maliki’s Daawa Party, were deported by Saddam before the war because they were of Iranian origin.

Many Iraqis consider raising posters of Iranian leaders as a sign of growing Iranian presence in Iraq. Others see the posters as a visual reminder of the physical and emotional pain Iraqis endured during the Iran-Iraq war as Khomeini refused over eight years to accept a ceasefire.

Iraqi Shias are mostly Arabs and advocate a strong Iraqi nationalism. There is a considerable minority of Shias among ethnic Kurds and Turkomans.

The posters highlight grave concerns over just how much influence Iran has been wielding in Iraq since the US invasion in 2003 and whether Iraq’s Shias can remain independent of Iraq’s Shia neighbour.

The Iraqi government has distanced itself from the posters, with local media quoting officials complaining that municipal workers fear retribution from pro-Iranian militias if they try to take them down.

Some of the posters carry signatures of Shia groups close to Iran, such as Al-Badr Organisation, a Shia militia that fought alongside Iran in the 1980-88 war. Another militia, Asaib Ahl Al-Haq, has boasted that it launched the poster campaign.

Since the Islamic Revolution in Iran in 1979 posters have acted as effective tools to disseminate theological and political messages.

During the war with Iraq, posters of Khomeini and prominent Iranians killed in war served as powerful means for mobilisation and communication with a war-weary population

Their posters were designed for mass distribution and aimed towards the Iranian public to embed political and religious propaganda. Thousands of these images still adorn public squares in Tehran and other Iranian cities.

The Iran-Iraq war was one of the most devastating human tragedies of recent Middle Eastern history. Both countries suffered collateral human and economic damage.

On 20 July 1988, Khomeini accepted reluctantly a UN-arranged ceasefire after a series of humiliating Iranian defeats on the warfronts. He likened it to “more deadly than taking a poisoned drink”. His ambition was to topple Saddam’s regime and install a government led by Shias and friendly to Iran in Baghdad.

In his speech at the time, Khomeini said: “Our nation should not consider the matter closed.” Many Iraqis are still haunted by the spectre of the conflict and Khomeini and Khamenei’s posters underline a worrying message.