In an interview with Fairfax Media, Operation Inherent Resolve's official spokesman identified Mosul, north of Baghdad, as the next "big-ticket item" for international forces battling to destroy IS but foreshadowed more immediate and "intermediate" victories first.

Declaring IS a "losing team" which would find it harder to use the internet to lure young men from abroad into becoming jihadists, Colonel Warren said there were preliminary signs the flow of foreign fighters was beginning to ebb.

And he said any foreigner intent on travelling to the Middle East would be "hunted" and most probably killed and possibly by Islamic State.

Recapturing Mosul

Thousands of Iraqis are returning to the city of Ramadi, three months after local troops, backed by the Coalition airstrikes drove IS out of the capital, which was littered with mines and booby traps.

In Tikrit, between 90 and 95 per cent of residents have returned, a year after IS lost control of the city.

"The next big-ticket item is Mosul" said Colonel Warren, but he cautioned "that is some time away."

"There's lot of difficult fighting ahead before the battlefield conditions are set for the liberation of Mosul," he said.

He said the operation to take back Mosul would be extremely challenging because IS has had two years to fortify their city, as well as the Iraqi forces being co-ordinated out of Baghdad.

"So with every step north on the march north to Mosul the fight becomes more difficult for those two reasons."

He said the town of Hīt, northwest of Ramadi was all but under the control of Iraqi forces and foreshadowed the seizure of a town called Makhmur in the Tigris river valley.

"So there are these intermediate objectives leading up to the eventual liberation of Mosul," he said.

Colonel Warren refused to put a time-frame around when the Coalition was likely to liberate the city because doing so would flag the Iraqi's mission to the enemy and he added as another reason: "we're always wrong."

Britain's Foreign Secretary Phillip Hammond has previously said IS could be defeated by 2017 but Colonel Warren declined to give the same guarantee when asked.

"We learnt our lessons on timelines the hard way," he said.

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IS losses making recruitment harder

Defence analyst firm HIS Jane estimates IS has lost a quarter of its territory in the last fifteen months. Kenneth Pollack from the Washington based think-tank the Brookings Institute says IS has not launched a successful campaign since it took Palymra in May 2015. Syrian forces, backed by Russia, re-took the city late last month.

The Pentagon believes IS' losses are forcing the leadership into making bad decisions leading to further setbacks.

It cites the case of "Omar the Chechen" who the US believes its forces killed in an airstrike in March. Omar the Chechen was a senior figure in IS and dubbed the organisation's Defence Minister. He was reportedly sent to command forces in the north-eastern town Shaddadi, which was under pressure from the Syrian Arab Coalition (SAC).

"We quickly killed him from the air, taking out a capability they're going to need, he will be very difficult to replace," Colonel Warren said.

The global coalition, based in the UK, is upping its online counter-recruitment programs, distributing simple memes which set to counter the wild promises IS promises to would-be fighters.

It distributes simple memes, videos and other online materials exposing the reality of life under IS versus the organisations' claims such as the following example using the catchphrase or hashtag "Daeshlies."

Colonel Warren said efforts made by countries to stop would-be jihadis from leaving, as well as Turkey's better controls on its Syrian border, combined with the shrinking size of ISIS' self-declared caliphate, were beginning to "restrict" the flow of foreign fighters.

"ISIS, they're starting to lose, they really are and no-one likes to join a losing team," he said.

In its latest publication of its propaganda magazine Dabiq, Islamic State said that Brussels attack was a "reminder."

"Paris was a warning. Brussels was a reminder. What is yet to come will be more devastating and more bitter," the magazine says.

Aussies great partners

Colonel Warren praised Australia's contribution to the fight against IS but said the United States wanted all countries to do even more to stop further attacks on Western soil.

This is a position favoured by former Prime Minister Tony Abbott who expressed concern about the poor scale and slow pace of Australia's airstrikes when they began.

In August 2014 the coalition had dropped just 269 bombs on IS targets. Twelve months later this increased to 2758. This was directly linked to the advances made by the Iraqi forces on the ground – as they forced militants to reposition from their hideouts.

"If you're sitting in your foxhole, you have two choices, stay and get killed or reposition," Colonel Warren said.

"The minute you get out of your foxhole, guess what there's an Australian F/A-18 ready to blow you to bits," he said.

Last month the Australian Defence Force released footage of two of the Air Task Group's 110 strikes carried out since the start of the year. The ADF said four Australian F/A-18 Hornets dropped eight 2,000 pound bombs in January and successfully destroyed a "significant percentage" of IS' weaponry stored in underground tunnels in Central Syria.

780 Australian Defence personnel have been deployed to the Middle East to help fight IS.

Colonel Warren praised Australia as "great partners."

"We love working with the Australians," he said.

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