Fierce fighting between Islamic State militants and soldiers from the Iraqi Army has forced 28,000 residents of the Iraqi city of Tikrit to flee their homes in recent days. Citizens of the strategically important city, which lies midway between regime-capital Baghdad and the ISIS stronghold of Mosul, are making desperate efforts to escape the fighting, the UN says. More than 30,000 Iraqi Army soldiers are currently fighting ISIS militants in the suburbs of Tikrit, or are otherwise making their way towards the city alongside tens of thousands of Iran-backed Shia volunteer militias, many of whom are accused of carrying out ISIS-style atrocities themselves. Although the troops are aiming to liberate the  city from ISIS control, many of the predominantly Sunni population have spent the past few days cutting up white clothes and fabric to make flags of surrender, fearing the Shia armies even more than their terrorist occupiers. Scroll down for video . Firepower: Shia fighters launch a rocket towards Islamic State militants during heavy fighting east of the militant-held city of Tikrit . Blast: Shia fighters launch a rocket towards ISIS targets near Tikrit. ISIS responded by setting fire to oil wells in the Ajil field east of the city . Preparing to fire: An Iraqi Army soldier makes the V-for-victory symbol before attacking an Islamic Strate target . Preparing for war: Iraqi soldiers are photographed on duty at a military barracks in Alam town, south of Tikrit earlier this week . Preperation: Shia fighters load rockets into a launcher during heavy fighting against Islamic State militants in Salahuddin province yesterday . Destruction: An Iraqi soldier looks on as smoke rises from oil wells set alight by ISIS militants near Ajil, east of the city of Tikrit . Most residents of Tikrit fled in the months after the extremist group took over in June. Those who stayed have fled in recent days, but a tiny fraction are still there, awaiting their fate. 'Some people say they would rather die in their own homes,' said 37-year-old Abu Saif, who sought refuge in Kirkuk after leaving Tikrit yesterday as the Iraqi army and Shia militants advanced. The forces have made gradual but steady progress, slowed by bombs and snipers as they approach from the north, south and east. They have yet to enter the city itself, but could soon launch attacks on the adjacent towns of al-Dour and al-Alam. 'The situation is frightening,' Abu Saif said. 'We are more afraid of the Hashid Shaabi, because they are seeking retribution.' Thousands of ISIS militants have poured into the city from other parts of the group's self-proclaimed caliphate and are preparing to fight to the death, said Abu Saif, predicting the battle would be long and bloody. Taking their rest: Iraqi soldiers relax behind a sand berm ahead of battles with Islamic State extremists outside Tikrit yesterday afternoon . Troops: More than 30,000 Iraqi Army soldiers (pictured) are currently fighting ISIS militants in the suburbs of Tikrit, . Battle: The Iraqi soldiers (pictured) are making their way towards the city alongside tens of thousands or Iran-backed Shia volunteer militias . A woman grieves during the funeral procession for six members of the Shia group, Asaib Ahl al-Haq, or League of the Righteous, killed in Tikrit . Convalescents: Volunteer fighters wounded during fighting with Islamic State extremists recover in a hospital in Baghdad . A Shia fighter injured in battles with ISIS terrorists near the militant-held city of Tikrit is photographed recovering in a Baghdad hospital . Fleeing residents admitted many of them had initially welcomed the militants as saviours from the oppression they felt under the Shi'ite-led government that came to power after Tikrit-born strongman Saddam Hussein was overthrown in 2003. They came to resent their presence after the extremist group began executing people it considered a threat, failed to provide public services, banned smoking and forced women to cover themselves. But they feared they would receive the same treatment as Sunnis in neighbouring Diyala province, where Shia militia have been accused of massacring civilians and torching their homes as they drove the militants out - charges they deny. 'We are between the hammer and the anvil,' said 32-year old Omar al-Tikriti, who managed to escape al-Alam several days ago with seven members of his family. 'Either we'll be burned by the fire of the (ISIS) militants, or the fire of the militias,' he added. Funerals: Members of a Shia group Asaib Ahl al-Haq flash victory signs during a funeral procession for six of their comrades . United: Mourners chant anti-ISIS slogans during funeral procession of six members of the Asaib Ahl al-Haq Shia militia . An Iraqi man mourns over a coffin during the funeral procession of members of Iraq's government forces and allied militias killed fighting ISIS . Grief: Mourners gather around coffins of members of Iraq's government forces who were killed fighting Islamic State terrorists . Anger: Qais al-Khazali (centre) the leader of the Shiite group Asaib Ahl al-Haq, or League of the Righteous, attends funeral procession of six members  of his militia who were killed in Tikrit fighting ISIS . Shia coalition: Mourners chant anti-ISIS slogans during funeral procession of six members of the Asaib Ahl al-Haq Shia militia . Some militia fighters have vowed to avenge the deaths of 1,700 Shi'ite soldiers who were killed by Islamic State militants when they overran Tikrit in June with the support of several local tribes. A spokesman for the Salahuddin tribal council said there was nothing to fear from the security forces or militia, and that Islamic State was spreading terror to rally Sunnis behind them. Marwan Jebbara pointed out that some 4,000 Sunnis were taking part in the campaign to retake Tikrit. Shia fighters advancing from the east have said they are accompanied by local Sunni people who are in contact with Tikrit residents to reassure them their safety will be guaranteed if they raise white flags when the fighters enter the city. A Shia cleric travelling with the advancing force reminded fighters they should respect civilians. But residents expressed deep unease about the involvement of Iran, which backs some of the militias involved in the assault. Iranian Revolutionary Guard commander Qassem Soleimani has been spotted on the eastern front, where he appears to be directing operations. Human Rights Watch yesterday said civilians in Tikrit were at 'serious risk' from both ISIS and government forces. 'All commanders in Tikrit need to make sure that their forces protect civilians and allow them to flee the combat zone,' said Joe Stork, deputy Middle East and North Africa director.
Thousands of Sunni residents of Tikrit have fled the ISIS-held city in fear of Iraqi regime forces and Shia militias . Locals have been living under the terror group's oppression for months - but they fear the Shia troops even more . Although the Iran-backed Shia volunteers aim to liberate Tikrit, they are accused of ISIS-style atrocities themselves . Now the Sunni locals are cutting up white clothes and fabric to make flags of surrender in fear of their lives .