Shrine attack that killed at least 40 is a sign that Islamic State is trying to reignite Shia-Sunni fighting, officials say

Islamic State suicide bombers reportedly disguised as local militia tried to storm one of Iraq’s main Shia shrines in the most serious attack on a holy site since the destruction of another such shrine a decade ago sparked the country’s sectarian war.

The bombers, aided by gunmen, fought through a marketplace in Balad to the Sayyid Muhammad bin Ali al-Hadi mausoleum where they blew themselves up near its main gates. Iraqi officials claim the Thursday night attack was the most brazen attempt yet by Isis to reignite sectarian chaos.

At least 40 people died in the attack and, while the shrine was not damaged, its gates were scorched by the blasts and fire that destroyed the market.

The assault followed a devastating explosion and resulting inferno in central Baghdad a week ago, which Iraqi officials say killed more than 290 people. If that is confirmed as the final death toll, it will likely rank as the deadliest single attack in Iraq since the war to oust Saddam Hussein 13 years ago.

Isis is under sustained pressure to hold on to the territory it claimed two years ago when it rampaged through western and central Iraq, overrunning Mosul, Tikrit, Ramadi and Falluja, and menacing Baghdad.

Mosul is the only Iraqi urban centre remaining in the hands of Isis, although it retains control of much of Anbar province and the border with Syria. Iraqi forces and Shia militias have spent much of the past year consolidating control of areas near Shia holy sites, fearful that militants may target them as they did in two strikes against the Imam al-Askari shrine in Samarra in 2006.

Those attacks, the first in February of that year and the second in April, led to large-scale bloodletting and mass displacement across Iraq, pitching the two main sects of Islam against each other, just as Abu Musab al-Zarqawi, the leader of a forerunner to Isis, had envisaged.

Ten years later, sectarian tensions, which have simmered throughout, have again been tested by the rise of Isis, which regularly bombs Shia targets. The country’s Sunnis, meanwhile, say they have remained severely disenfranchised at the hands of the Shia majority, which will not meaningfully share power with them.

However, tensions have not neared the toxic heights of 2006 and political leaders and tribal figures on Friday asked for citizens to put their faith in the government to stop the attacks.

After controlling geographical areas for several years, Isis now appears to be reverting to its old ways of attacking Shia religious sites and soft civilian targets, such as the Karrada shopping district, which was the scene of the Baghdad blasts last weekend.

Dr Mustafa al-Sufi, who lives near the site of Thursday’s attack said: “There are some people in Balad who are accusing the refugees and the Sunnis of inciting this.”

Most of Iraq’s internally displaced people come from Sunni areas that were besieged by Isis. Many of them have been kept out of Baghdad and have looked for shelter in towns and villages on its outskirts. “But I don’t believe we will get back to the dangers of 2005-06,” Sufi said. “Because there remains some discipline in the street so far.”

A tribal leader from Balad, Sheikh Abu Salam Saede said: “They aim to restart sectarian violence. And this is because of the Saudi ambassador and it shall be war to the judgment day if they don’t remove him. This is 100% because of their defeat in Falluja.”

Security officials believe two Isis units that were responsible for major bombings in Baghdad in 2009 have been reformed to conduct a series of new attacks and were responsible for the one in Karrada.

Before the Balad blast, an Iraqi security official told the Guardian that a Shia shrine would be a likely next target. “This is a sign of [Isis leader, Abu Bakr al-]Baghdadi’s desperation,” he said. “It does not speak to his strength.”

ѕoℓyαηıм нerşeyiм (@YuregiminEzgisi) Barbar IŞİD, Irak Balad'da Şiilerin ziyaret ettiği türbeye bombalı araçla saldırı gerçekleştirdi en az 50 kişi öldü! pic.twitter.com/AqjfnqZwEM

Iranian-backed militia and Iraqi security forces have invested enormous resources in protecting Shia shrines in Baghdad, Najaf and Karbala. The breach of the mausoleum site in Balad was causing ramifications on Friday, with powerful rival militias Asa’ib ahl al-Haq and Saraya Salam accusing each other of security lapses.

The suicide bombers are believed to have driven into the compound, which contains the marketplace and shrine, by posing as members of a local militia. Once inside, they attacked a small guard force and fought their way to the gates.

On Friday morning, the prime minister, Haider al-Abadi, announced the sacking of several senior security officials in Baghdad, including the general responsible for the capital’s security. The move follows the resignation of Iraq’s interior minister after the Karrada bombings.

The rare burst of accountability was met with wariness by many in Baghdad, who have become disillusioned over years of attacks, which residents partly blame on official incompetence. After authorities had continued to use fake British-made bomb detectors over the past decade, Abadi finally ordered them removed from checkpoints across Iraq earlier this week and ordered a shelved corruption inquiry into their procurement to be reopened.

“That will never happen,” said Mustafa Saad, an engineer from the suburb of Baladiyat. “There are too many people invested in making sure that their deeds are not exposed. At least soldiers will have to look for bombs with their eyes now.”

Additional reporting by Saud al-Murrani