Battle between terror group and Shia fighters there would be 'utter carnage'

ISIS has 'surrounded' Iraqi capital and wants 'all-out war' with militia there

ISIS militants have held a twisted victory parade after taking the key city of Ramadi in an orgy of violence and beheadings - and the extremists could march on the Iraqi capital Baghdad within the next month.

Mutilated bodies scatter the streets of the 'Gateway of Baghdad', where Islamic State slaughtered around 500 and forced nearly 25,000 to flee their homes over the last few days.

Now ISIS has released images of militants celebrating, children wielding automatic weapons and a fleet of pick-up trucks carrying its jubilant fighters through the blood-stained streets of Ramadi.

Shi'ite fighters have already launched a counter-offensive to recapture the city, but these kinds of tactics play straight into Islamic State's grand plan to spark all-out war in the region, according to the Middle East director of counter-terrorism think-tank RUSI.

Islamic State militants are already marching east towards the Habbaniya army base - around 20 miles east of Ramadi - where a column of 3,000 Shi'ite paramilitaries are amassing, witnesses and a military officer has said.

And if ISIS manage to reach Baghdad, it would be 'utter carnage', Professor Gareth Stansfield told MailOnline.

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Show of strength: ISIS flags line the streets of Ramadi as a procession of militants - riding on the backs of Toyota Land Cruisers - parade through the city

Surrounded: ISIS already has control of Fallujah which is on Baghdad's doorstep and has now conquered the strategically important city of Ramadi further west. It has Sunni support to the south of the Iraqi capital and is waging battles with security forces in the north to effectively 'surround' Baghdad

Parade: After slaughtering 500 people and forcing over 8,000 from their homes, ISIS triumphantly drive through Ramadi (pictured) in a fleet of pick-up trucks

Sick: One twisted image released through Islamic State's social media channels shows a small child carrying what appears to be a mortar shell in Ramadi - after their victory in the city

Insurgency: The city where ISIS militants fired rocket propelled grenades contains sacred Shi'ite shrines which - if destroyed - would force the militia to take on ISIS head on, experts have said

Innocence lost: ISIS has released pictures showing its militants - and young followers (pictured) - celebrating the capture of Ramadi as Shi'ite militias prepare a counter-offensive to retake the city

He said: 'If ISIS turn up in great numbers in Baghdad, it will be an absolute slaughter between Sunni's and Shia's there.

'They [ISIS] are now having so many successes, and moving so quickly, that Baghdad is under very real threat from ISIS forces outside Baghdad and also the ISIS terror cells inside Baghdad as well.

'We're in for a very long summer of fighting in Iraq and ISIS could make their move [on Baghdad] in the next month. Taking Ramadi will... make the Shia militia in Baghdad even more radicalised and more dangerous.

'And this is what ISIS wants, it wants it to come out and have sectarian scrap which forces all the Sunni's to go towards ISIS.

Pincer attack: As reports flood in that ISIS has taken over Ramadi, its militants have also been battling security forces in Samarra (pictured), around 70 miles north of Baghdad

Celebration: Hundreds of ISIS fighters carrying the notorious black flag of jihadi groups celebrate in the blood-stained streets of Ramadi (pictured)

Moving on: The ISIS militants who are celebrating battlefield success in Ramadi could soon march to Iraq's capital Baghdad just 60 miles east, experts claim

Cut down in cold blood: Pictures posted on Twitter show bodies of Iraqi soldiers lying strewn across a street in Ramadi after ISIS militants carried out mass killings during their capture of the strategic city

Murdered: A Sunni tribal leader said many tribal fighters died trying in vain to defend the city

'If they had any opportunity to enter Baghdad, they would do. But it will be more and more difficult for them to do it because Baghdad is a military stronghold of the Shia militia.'

And if they manage to actually take Baghdad, which is predominantly Shia but has some Christian regions, Professor Stansfield says 'there would be massacres to the scale we haven't seen since the Mongol empire in the 13th Century'.

The UN said tonight that close to 25,000 people have fled Ramadi after militants attacked the city.

United States-led airstrikes have stepped up raids against the Islamists, conducting 19 strikes near Ramadi over the past 72 hours at the request of the Iraqi security forces, a coalition spokesman said.

And as fighting rages in and around the city, Islamic State fighters are also taking on Iraq's military and tribal groups in the north.

Fleeing: Civilians ran from their homes in Ramadi after Islamic State militants started searching door-to-door for policemen and pro-government fighters

Terror: The streets of Ramadi descended into gridlock as civilians started fleeing from their homes today

Federal police forces arrived from Baghdad and created a barricade to protect the Habaniyah military base near Ramadi

Thousands of ISIS extremists paraded through the streets of Ramadi after capturing the city

Shocking: Images found on Islamic State's various social media channels show tiny children celebrating alongside the militants in Ramadi, where the militants have already begun to execute captives

Villains: If ISIS (pictured) take Baghdad, 'there would be massacres to the scale we haven't seen since the Mongol empire in the 13th Century.' an expert claimed

ISIS are using rocket-propelled grenades to take on the Shi'ite militia 'Popular Mobilisation' in the city of Samarra, 70 miles north of the capital, according to Institute for the Study of War.

Equally brutal battles are taking place in Nebai just 50 miles to the north-west of Iraq, where ISIS has reportedly used 'various weapons' against Iraqi security forces and tribal fighters.

Professor Stansfield added: 'Baghdad is in some ways already surrounded but now it's lost Ramadi, this now brings the spectre of ISIS extremely close to Baghdad.'

'If you piece together where ISIS has control, it has Baiji which is much further north but still somewhere the Iraqi forces are having to fight.

'You've got ISIS very strong in Fallujah to the west of Baghdad and you've got ISIS pretty safe in Mosul.'

Pictures released by Isis purportedly show the terror group releasing prisoners from Ramadi having stormed into the city. A gun was fired at locks securing cells in the city's jail

Militants have not yet revealed how many prisoners they have freed from the jail in Ramadi

According to Iraqi security forces, most of the high-valued prisoners had already been moved from the jail to other detention centres

The loss of Ramadi - the capital of Iraq's largest province Anbar - was the military's worst setback since it started clawing back territory from the Islamic State group late last year.

Chilling images showing the totality of their defeat there show ISIS militants celebrating openly in the streets among dozens of charred bodies.

One man appears to have been captured by the merciless militants, who filmed the man's terrified expression before brutally beheading him on camera.

Other videos showed Humvees, trucks and other equipment speeding out of Ramadi, with soldiers gripping onto their sides in a desperate and chaotic retreat.

Regarding how many people have died there in total, a spokesman for the Anbar province's governor said: 'We do not have an accurate count yet.'

Twisted: The picture of a man who supposedly carried out this suicide bombing in Ramadi featured in one of the many propaganda videos released by ISIS, in the wake of their victory in the city

Butchered: Around 500 people are understood to have been killed over the past few days as the capital of Iraq's Anbar province fell to the terror group

Death: Their bodies, some charred, were strewn across roads while others had been thrown in the Euphrates River

Edging closer: The loss of the capital of Iraq's largest province (shown on map) marks one of Baghdad's worst setbacks since it began a nationwide offensive last year to reclaim territory lost to ISIS

Wrecked: A triumphant ISIS militants poses next to a destroyed tank - which bares the flag of Iraqi's military

Muhannad Haimour added: 'We estimate that 500 people have been killed, both civilians and military, and approximately 8,000 have fled the city.'

Baghdad is in some ways already surrounded but now it's lost Ramadi, this now brings the spectre of ISIS extremely close to Baghdad Professor Gareth Stansfield, RUSI

The estimates are for the past three days, since Friday, when the battle for the city reached its final stages.

The 8,000 figure is in addition to the enormous exodus in April, Haimour said, when the U.N. said as many as 114,000 residents fled from Ramadi and surrounding villages at the height of the violence.

Local officials have said that ISIS carried out mass killings of Iraqi security forces and civilians.

With defeat looming, Prime Minister Haider al-Abadi had ordered security forces not to abandon their posts across Anbar province, apparently fearing the extremists could capture the entire desert region that saw intense fighting after the 2003 U.S.-led invasion to topple dictator Saddam Hussein.

Earlier Sunday, al-Abadi ordered Shi'ite militias to prepare to go into the Sunni-dominated province, ignoring U.S. concerns their presence could spark sectarian bloodshed.

By late Sunday, a large number of Shi'ite militiamen had arrived at a military base near Ramadi, apparently to participate in a possible counter-offensive, said the head of the Anbar provincial council, Sabah Karhout.

Carnage: ISIS have taken full control of the Iraqi city of Ramadi after security forces fled the area following a series of suicide car bombings. Pictured: A car is engulfed in flames during clashes in the city

Horror: An Iraqi man captured by ISIS during their siege on Ramadi looks terrified in one of their propaganda videos - in which he is later seen decapitated

Spoils of war: Other pictures posted online purportedly show Islamic State militants celebrating after capturing military vehicles abandoned by fleeing Iraqi security forces

Jubilant jihadis: On a militant website frequented by ISIS members, a message from the group claimed its fighters held the 8th Brigade army base as well as tanks and missile launchers left behind by fleeing soldiers

Conquered: ISIS jihadi's celebrate taking the town of Ramadi which lies just 60 miles west of Iraq's capital Baghdad

U.S. Secretary of State John Kerry said he remained confident about the fight against the Islamic State group, despite the setbacks like the loss of Ramadi.

Kerry, travelling through South Korea, said that he's long said the fight against the militant group would be a long one and that it would be tough in the Anbar province of western Iraq where Iraqi security forces are not built up.

Sunday's retreat recalled the collapse of Iraqi security forces last summer in the face of the Islamic State's blitz into Iraq that saw it capture a third of the country, where it has declared a caliphate, or Islamic State.

It also calls into question the Obama administration's hopes of relying solely on airstrikes to support the Iraqi forces in expelling the extremists.

'We welcome any group, including Shi'ite militias, to come and help us in liberating the city from the militants.

'What happened today is a big loss caused by lack of good planning by the military,' said Sunni tribal leader Naeem al-Gauoud.

Battle front: Islamic State militants inspect military vehicles abandoned by Iraqi troops as they fled the city

Bolstering arms: Sunday's retreat recalled the collapse of Iraqi security forces last summer in the face of the Islamic State's blitz into Iraq

Victory: Images obtained from Islamic State's social media channels show the militants celebrating an apparent victory in the city of Samarra (pictured)

Spoils of war: An Islamic State propaganda video showed the huge cache of weapons the insurgents seized from their conquered enemy in Samarra

He said many tribal fighters died trying to defend the city, and bodies, some charred, were strewn in the streets, while others had been thrown in the Euphrates River.

The final ISIS push to take Ramadi began early Sunday with four nearly simultaneous bombings that targeted police officers defending the Malaab district in southern Ramadi, a pocket of the city still under Iraqi government control, killing at least 10 police and wounding 15, officials said.

Among the dead was Colonel Muthana al-Jabri, the chief of the Malaab police station.

Later, three suicide bombers drove their explosive-laden cars into the gate of the Anbar Operation Command, the military headquarters for the province, killing at least five soldiers and wounding 12, the officials said.

The extremists later seized Malaab after government forces withdrew, with the militants saying they controlled the military headquarters.

A police officer who was stationed at the headquarters said retreating Iraqi forces left behind about 30 army vehicles and weapons that included artillery and assault rifles.

Bombing run: The crushing defeat sent Iraqi forces fleeing in a major loss of territory just 60 miles from Baghdad despite the support of U.S.-led airstrikes (seen above) targeting the extremists

Coalition forces blitzed key targets, but it did little to stop ISIS taking control of the provincial capital

He said some two dozen police officers went missing during the fighting. The officer and the other officials spoke on condition of anonymity as they were not authorised to talk to reporters.

On a militant website frequented by ISIS members, a message from the group claimed its fighters held the 8th Brigade army base, as well as tanks and missile launchers left behind by fleeing soldiers.

The statement said: 'God has enabled the soldiers of the caliphate to cleanse all of Ramadi... after storming the 8th brigade.'

The message could not be independently verified, but it was similar to others released by the group and was spread online by known supporters of the extremists.

Last week, the militants swept through Ramadi, seizing the main government headquarters and other key parts of the city.

Online video showed Humvees, trucks and other equipment speeding out of Ramadi, with soldiers gripping onto their sides in a desperate and chaotic retreat

Muhannad Haimour, spokesman and adviser to the governor in the province of Anbar, said 'Ramadi has fallen' to ISIS. Pictured: Displaced Iraqis from Ramadi gather as they flee their hometow

It marked a major setback for the Iraqi government's efforts to drive IS out of areas the group seized last year. Previous estimates suggested the Islamic State group held at least 65 percent of the vast Anbar province.

Backed by U.S.-led airstrikes, Iraqi forces and Kurdish fighters have made gains against the Islamic State group, including capturing the northern city of Tikrit.

But progress has been slow in Anbar, a Sunni province where anger at the Shiite-led government runs deep and where U.S. forces struggled for years to beat back a potent insurgency.