Demonstrators grow ever more determined to force real political change in Iraq despite a bloody crackdown which left over 20 dead

The gunshots emptied protesters from Baghdad’s Khilani square in minutes, but as nearby streets filled with the crush of people running for their lives, two men stayed on, waving a vast Shia banner in defiance of the bloodshed around them.

The pair must have known they were in the gunmen’s crosshairs, and soon one of them crumpled, hit by a bullet. But their determination to continue was a powerful message to authorities and militias trying to crush Iraq’s popular uprising by force.

Activists say 23 people were killed on Friday night in the deadliest incident to hit the Iraqi capital in weeks of protests. Among them was a photojournalist, Ahmed Mehana, who had survived reporting on the frontline against Isis. His brother said he had been stabbed in the back while covering the demonstration.

At least 400 people have died since protesters first took to the streets at the start of October to denounce corruption, unemployment, failing public services and Iran’s heavy influence on the country’s politics.

The leaderless movement has gathered momentum despite this heavy toll, and the authorities’ heavy-handed response has fuelled growing outrage in Iraq and abroad.

On Friday, the United States said it had imposed sanctions on three militia leaders for their role “in the brutal crackdown on peaceful protesters in Iraq”, and a fourth businessman accusing of “bribing officials and engaging in corruption”.

Prime Minister Adel Abdul-Mahdi has formally submitted his resignation over the protests, but he will continue to serve in a caretaker government until a replacement can be approved in parliament.

That could take weeks or even months, as multiple feuding factions try to broker a compromise. Mahdi’s own appointment last year only came after five months of wrangling, and an intervention by Iranian officials.

Any attempt by Tehran to intervene again could be explosive; protesters have already attacked and burned the country’s consulate in the southern city of Najaf.

Facebook Twitter Pinterest Anti-government protests in Baghdad last month. Photograph: Khalid Al-Mousily/Reuters

Shortly before violence broke out on Friday, the most senior Shia cleric in the country had called on parliament to choose his replacement within a deadline of 15 days, and without foreign interference.

“We hope the head of the new government and its members are chosen within the constitutional deadline and according to the aspirations of the people and away from outside influence,” Grand Ayatollah Ali al-Sistani said in his weekly Friday sermon, delivered as always by a representative in the holy city of Najaf. He added that the Shia religious establishment would not take part in the process of forming the next government.

The killings in Baghdad were the latest in a series of attacks on protesters by gunmen, many by Iran-backed militias like the ones whose leaders were sanctioned by the US.

After the sermon, protesters flooded into the streets across the country, and in Baghdad they headed on to three bridges near or leading to the heavily fortified green zone, the seat of Iraq’s government, which have been occupied for more than a month.

The massacre began around 8pm. Footage from the protest site shows a column of four white pickup trucks carrying gunmen, followed by three buses, driving into Khilani square accompanied by the sound of gunfire.

Electricity to the area had been turned off, and the shooting sparked chaos in the dark. Scores of demonstrators ran for cover, while others carried the injured to seek first aid, as the tuk-tuk rickshaws that have served as makeshift ambulances sounded their horns.

The area was then lit up by flames when gunmen, who were dressed in civilian clothing, set fire to a multi-storey car park that the demonstrators had taken over. A spokesman for the interior ministry said later that only four people had been killed and that the government would open an investigation into the incident. Police and medical sources told Reuters that, along with the 23 deaths, more than 127 people had been injured.

The dead included men who had been posted to the area as unarmed security guards after a string of suspicious stabbings in Tahrir square, the centre of the protest movement.

The guards were members of Shia cleric Moqtada al-Sadr’s militia, nicknamed the “blue hats”, and their killings raised fears of retaliation and factional fighting between groups supporting the protests and those trying to crush them.

But in a sign of the protesters’ defiance, demonstrators were flocking back towards Khilani square within an hour of the shootings.

“The pro-Iranian camp know that their large bloc in parliament will disappear in the next elections once electoral reforms are implemented, so they are resorting to violence trying to ignite internal strife,” said Sarmad al-Tai, an Iraqi writer and journalist.

“But they can’t understand that these demonstrations are a moment of national Iraqi pride and can’t be defeated by violence. They failed yesterday just as they failed in Nasiriyah and Najaf before.”

Protest camps in Tahrir square had already taken on a more permanent aspect before the latest shootings, with everything from street theatre and memorials for the dead to a volunteer street clean-up team. Last week, young men and women in high-vis vests and armed with brooms and shovels cleared the thick layer of rubbish accumulated over weeks of protests, bagging up gas cannisters, plastic bottles and blankets to leave the area cleaner than most residents remember it ever being.

Tents made of blue tarpaulin have been set up to shelter students, tribespeople, medics and other groups from the winter cold; between them pedlars sell biscuits and fruit.

In a tent bearing the words the “people’s theatre” poetry recitations and experimental theatre performances are held. Beyond it sit a dozen or so “shrines for the martyrs”, a solemn reminder of the terrible human cost of the uprising and the real risks everyone in the square is running just by being there.

Pictures of the dead, mostly young men in their late teens or early twenties, are placed on the ground, surrounded by plastic flowers, copies of the Qur’an and incense sticks. In front of them gathers a steady stream of people who kneel, light candles and then sit with their grief, in silence broken only by a deep sob and a heaving of shoulders.