London- More than 40,000 civilians were killed in the devastating battle to retake the northern Iraqi city of Mosul from ISIS, according to intelligence reports revealed to Britain’s The Independent – a death toll far higher than previous estimates.

Many bodies are still buried under the rubble and the level of human suffering is immense, the reports said.

Residents of the besieged city were killed by Iraqi ground forces attempting to force out militants, as well as by air strikes and ISIS militants, according to Kurdish intelligence services.

Hoshyar Zebari, Iraq’s former foreign minister, told The Independent that many bodies “are still buried under the rubble.”

“The level of human suffering is immense,” he said.

“Kurdish intelligence believes that over 40,000 civilians have been killed as a result of massive firepower used against them, especially by the federal police, air strikes and ISIS itself,” Zebari added.

Zebari, a native of Mosul and top Kurdish official who has served as the Iraqi finance minister before becoming foreign minister, emphasized in an exclusive interview with the British daily that the unrelenting artillery bombardment by units of the Iraqi federal police, in practice a heavily armed military unit, had caused immense destruction and loss of life in west Mosul.

The figure given by Zebari for the number of civilians killed in the nine-month siege is far higher than those previously reported, but the intelligence service of the Kurdistan Regional Government has a reputation for being extremely accurate and well-informed, according to The Independent.

ISIS prevented any monitoring of casualties while outside groups have largely focused on air strikes rather than artillery and rocket fire as a cause of civilian deaths. Airwars, one such monitoring group, estimated that attacks may have killed 5,805 non-military personnel in the city between 19 February and 19 June.

Zebari accuses the government in Baghdad, of which he was until recently a member, of not doing enough to relieve the suffering. “Sometimes you might think the government is indifferent to what has happened,” he said.

Zebari says that a high level of corruption among the Iraqi military forces occupying Mosul is undermining security measures to suppress ISIS in the aftermath of its defeat.

He says that suspect individuals are able to pass through military checkpoints by paying $1,000 (£770) and can bring a vehicle by paying $1,500.