The rebuilding of vast swathes of Iraq and Syria damaged and destroyed in the brutal war against Islamic State is "critical" to stop the terror group rising from the rubble.

Dangerous pockets of IS fighters remain stubbornly holed up in eastern Syria, but the territory now under their control is a fraction of the self-styled caliphate they ruled with barbaric violence in mid-2014.

Despite the dismantling of the so-called caliphate, which once covered a third of Iraq and much of Syria, the total eradication of IS seems unlikely any time soon.

Data from Airwaves, a combat monitoring group, showed IS have survived more than 100,000 bombs dropped on them by US-led airstrikes, including six Australian F/A-18F Super Hornets.

Ahead of an anti-ISIS coalition ministerial meeting in Brussels tomorrow, Donald Trump's top Islamic State military advisor, Brett McGurk, has just finished a five-day trip to Syria.

McGurk today tweeted that "follow through is critical" to stop IS regenerating. Photos taken from the air by McGurk show agricultural projects fostered by the coalition turning "once brown fields green and bountiful" in north-east Syria.

"Much more work to do in both [Iraq and Syria] to recover from ISIS," he tweeted.

The sustained US-led airstrike campaign has totalled 1431 days since former US President Barack Obama ordered its commencement in August 2016. A total of 107,814 bombs and missiles have been dropped on targets in Iraq and Syria, according to Airwaves data.

The group claims a minimum of 6321 civilians have been killed in 29,772 sorties (15,500 in Syria and 14,272 in Iraq). That data does not include ordinance dropped by Russian fighters and planes, which began in late 2015.

In support of the US-led coalition, Australia deployed an Air Task Group which included six Super Hornets, an E-7A Wedgetail surveillance aircraft and a multi-role tanker transport aircraft. The Air Task Group was ordered back to Australia in December last year, following the fall of key IS-held cities Raqqa in Syria and Mosul in Iraq.

Aside from rebuilding infrastructure and trying to kick-start local economies, efforts are underway to repair Islamic State's deliberate destruction of Palmyra, an ancient world heritage site. Eight Russian experts have begun reconstructing ancient statues and sculptures rescued from Palmyra, according to Russia's Defence Ministry.

IS ravaged the Roman-era ruins during the 10 months it held the ancient oasis city from May 2015 to March 2016. Footage and photos of extremist fighters systematically blowing up temples and columns provoked worldwide outrage.

Islamic State razed ancient shrines and statues it considered idolatry. The group was also suspected of illegally selling priceless antiquities to fund its army and self-proclaimed caliphate.

Palmyra, home to towering 2000-year-old ruins, is the scene of one of Russia's most embarrassing chapters in the conflict. After ten months under IS control, Russian-backed Syrian forces ejected the jihadi fighters from Palmyra in March 2016.

On May 5 the St Petersburg orchestra played a triumphant concert in the Roman amphitheatre, which was broadcast on Russian TV. However, six months later, Islamic State fighters retook Palmyra and proceeded to obliterate the once majestic amphitheatre where the classical musicians performed.

The militants destroyed Palmyra's two most glorious temples, dating back to the 1st century, and blew up the famous Roman Arch of Triumph. US envoy Brett McGurk's coalition meeting in Brussels will follow a top-level NATO meeting, attended by heads of government.

In July last year McGurk proclaimed any foreign fighters remaining in Raqqa, which at the time was surrounded by coalition forces, were doomed to die.

"The mission is to make sure ... that any foreign fighter who is here, who joined ISIS from a foreign country, who came into Syria, they will die here in Syria," he said. "If they are in Raqqa they are going to die in Raqqa."

Perth-born Tareq Kamleh, also known as 'Dr Jihad', was believed to be in Raqqa.

Unverified reports in June, which Nine.com.au exclusively reported, indicated Kamleh had been killed.