MOSUL, Iraq (Reuters) - When four rockets crashed into his east Mosul home in November, Abu Abdel Malik’s 60-year-old step-mother was killed instantly. But she wasn’t properly buried for more than a month.

Fighting in Zuhur district and surrounding areas was too intense during that period to transport the body to the main cemetery in the suburb of Gogjali, just 5 km (3 miles) away.

So Abu Abdel Malik along with his father, brother, son and nephew dug a shallow hole under an orange tree in the garden just steps from where the family matriarch had died, and laid her there.

“We could not leave, we were surrounded. There were snipers all around and the army was advancing,” he said last week, showing a Reuters reporter how the rockets had torn through the kitchen and set the trees on fire.

He asked to be identified only by his nickname, Abu Abdel Malik, to protect family members in areas still controlled by Islamic State.

As Iraqi forces sweep across much of eastern Mosul in a three-month, U.S.-backed offensive, residents remain in danger, often targeted they say by mortars and bullets fired by retreating Islamic State militants.

Civilians who cannot reach the city’s main cemeteries have resorted to burying their dead wherever they can, at least until the fighting moves further from their doorsteps.

When Abu Abdel Malik dug up his step-mother’s body last Saturday to inter it beside the family’s forebears in the Gogjali cemetery, he said it had begun to decompose and gave off a foul smell.

Residents in nearby al-Qadisiya al-Thaniya district expect to do the same in coming weeks. There, in the yard of a local elementary school are eight long mounds of dirt where civilians have buried friends and relatives killed in areas recaptured from Islamic State.

Among the dead is an elderly resident who had a heart attack and could not reach the hospital because of the fighting.

One local man, who asked not to be named fearing reprisals against his son who is stuck under Islamic State rule in western Mosul where the militants maintain full control, said he had buried a cousin and his two sons last week. They were killed in a mortar attack in Rifaq district while out buying eggs.

A cemetery for people who were killed in the clashes is seen at a grave in a schoolyard east of Mosul, Iraq, January 11, 2017. Picture taken 11, 2017. REUTERS/Ahmed Saad

A cardboard sign marks the grave of the cousin, Ali Hussein. Spray paint on the gray concrete wall nearby indicates where others are buried.

“We will move them all, of course, when this nightmare is over,” the man said.

A ninth shallow pit remains empty, in seeming anticipation of the war’s next victim.

ISLAMIC STATE BURIALS

The Mosul campaign, involving a 100,000-strong alliance of Iraqi government troops and militarized police, Kurdish security forces and mainly Shi’ite Muslim militiamen, is the most complex battle in Iraq since the U.S.-led invasion in 2003.

Throughout the fighting, most residents have stayed in the northern city, Islamic State’s last major stronghold in the country and the largest urban center anywhere across its self-styled caliphate in Iraq and neighboring Syria.

That has complicated the task of Iraq’s military, which must fight among up to 1.5 million civilians in built-up areas against an enemy that has targeted non-combatants and hidden among them.

Adjacent to the schoolyard gravesite in al-Qadisiya is an open field which residents said was the site of a fierce confrontation last year between advancing Iraqi forces and Islamic State militants.

An exterior wall was knocked through and other school buildings have been heavily damaged by rockets and suicide bombers. Weeks after the clashes, a few charred body parts are still visible.

One explosion had carved a crater in a cement patio. It is now filled in with brown dirt.

Residents say they buried half a dozen Islamic State fighters in the hole after their bodies lay decomposing on the streets for two weeks. There are no gravestones or marks to identify what lies below.

“We asked the army to do something about the corpses and they told us to bury them, so we put them here,” said Alaa Moqdad Mostafa, 35.

Down the road in the Muharibeen district, an elderly resident says another three Islamic State bodies are buried in an empty lot where residents have taken to throwing their rubbish.