BEIRUT: Having taken land five times the size of Lebanon, and establishing the first “caliphate” in nearly 100 years, the rapid advances of ISIS are dominating headlines around the world and instilling fear in many across the region.

But experts believe their military capabilities may have been embellished, and that they are not as strong as their slick media campaign makes out.

Headquartered in Raqqa, eastern Syria, the Islamic State of Iraq and Greater Syria made rapid advances across Iraq in early June, capturing Mosul and much of the surrounding Nineveh province, and taking Tikrit, Saddam Hussein’s hometown.

In much of this conquered land, ISIS met Iraqi army forces who simply retreated, not even attempting to put up a fight, and discarding their uniforms and vehicles as they left.

“ISIS just don’t show me a real strong combat capability,” said Jeff White, defense expert at the Washington Institute, who specializes in the Middle East.

“They are good at ambushes, and good at planting mines, killing civilians and driving through the desert. But that’s not fighting.”

ISIS is estimated to have somewhere between 8,000 and 12,000 members, but, as White pointed out, many thousands of these are in Syria, and “there is always a difficulty in counting these irregular forces” as some may be part-time members.

When Iraq’s second-biggest city fell to ISIS, White believes it wasn’t a question of serious fighting, but that the mass desertions on the part of the Iraqi army allowed ISIS to take Mosul.

“If the accounts are true that they took Mosul with 700 or 800 people, that certainly doesn’t reflect any serious fighting,” he said.

“All the accounts we have are that the Iraqi government forces collapsed, hollowed out by desertions. They lacked any cohesion, leadership was poor and largely abandoned the troops.”

The weakness of the Iraqi army “has certainly been useful to them, which is why they were able to take such a large amount of territory in central and northern Iraq so quickly,” said John Drake, Iraq analyst with the AKE security group.

“They have also used propaganda and a long-campaign of terrorism which has lowered security force morale,” he added. Over the last year, terror attacks, many attributed to Al-Qaeda inspired groups, including ISIS, have increased in frequency across Iraq, with car bombs and suicide missions occurring almost daily.

But while ISIS has clearly relied on the weakness of the Iraqi military, agreed Charles Lister, visiting fellow at the Brookings Doha Center, “a great deal of this weakness is a direct result of ISIS’ long-time strategy of intimidation and kinetic undermining of security force capabilities.”

In Mosul, for example, Lister said, ISIS maintained databases containing personal information on local security and government officials. “It was through this kind of information that ISIS maintained a constant campaign of intimidation, which gave the group a kind of all-seeing image amongst its enemies.”

It’s likely that Iraqi soldiers, lacking direct combat experience, may also have been intimidated by ISIS’ presumed experience, with many members having already been in Syria for several years.

“A notable proportion has presumably had experience fighting, and surviving, conflict in neighboring Syria,” Drake said .

“It is certainly arguable that a lot of the fighters have had more experience in direct combat than the Iraqi security forces, many of whom have simply been manning checkpoints over recent years rather than engaging in active fighting on the ground,” he added.

But White doubted how much time spent in Syria had really benefited the ISIS insurgents now in Iraq.

“By the nature of the way ISIS has fought in Syria, they haven’t fought a lot of serious battles: they have been more opportunistic in their battles. And when they have encountered serious challenges in Syria, they have tended to fall back,” he said.

This has been true for the Iraq situation also, White and Drake agreed. When ISIS faced Kurdish peshmerga forces in the north, ISIS weaknesses became apparent.

In contrast to their impressive gains in Ninevah, “they have struggled to make headway in conflict with the better trained Kurdish security forces,” Drake said, and White said: “When we have seen more serious fighting, in Baiji, and some of the fighting against the Kurds, ISIS just hasn’t done that well.”

The battle for Baiji, Iraq’s biggest oil refinery is ongoing, and Friday, government airstrikes targeted militants’ vehicles, killing 30, according to counterterrorism spokesperson.

“In terms of serious combat capability, I think it’s been exaggerated,” White said, adding that it has been hard for ISIS to take any well defended positions.

While a recent military parade in Raqqa allowed ISIS to show off captured equipment that was originally given to the Iraqi army by the U.S., “we have yet to see that integrated” into their fighting operations, he said.

But Shiraz Maher, senior fellow at the International Centre for the Study of Radicalization, King’s College London, thinks that Abu Bakr al-Baghdadi, self-styled caliph of ISIS, has been very clever in his approach so far, with ISIS commanders leading the battles, and local Sunni tribesmen doing the actual fighting.

“That’s the genius of ISIS: they are scaling up to reach a critical mass of fighters, by using local fighters,” Maher said.

“They’re holding an area roughly the size of Pennsylvania, with only 8,000-12,000 fighters. So you definitely need the locals.”

Since “losing” Iraq during the U.S. occupation, Al-Qaeda has reflected heavily on how that happened, Maher said, and a realization that they had to use local Sunni groups – which had fought against them the first time around – to defeat what was seen as a Shiite fiefdom, centered in Baghdad.

While we often hear a lot about the abject brutality of ISIS, they are also working hard to provide food and utilities to local residents in areas they have won, Maher said, and are “Putting in place all the framework of a civil society ... to win people over who have been living in terrible conditions.”

The biggest existential threat to ISIS right now is overstretch, Maher added, but if Baghdadi can maintain control over the areas it has, “I think it has all the hallmarks of a durable state.”

Many of the ISIS fighters he has spoken to are not fighting but on guard duty, working to secure the areas they have won. But ultimately, ISIS’s worldview will lead it further afield, to Jordan and Saudi Arabia, although incursions over these borders would likely bring in Israel and the U.S., respectively, Maher said.

“They’re not going to be at the borders of France any time soon, but they will push on into Jordan,” he said. “They have a narrow worldview: they have to take over the world.”