From guerrillas to conquerors: How ISIS has changed從游擊隊到征服者：如何ISIS已經改變
October 18, 2014 -- Updated 0858 GMT (1658 HKT)
Justin Bronk: ISIS is a guerrilla army that has captured large stocks of modern weaponry.
- Justin Bronk: The number of ISIS fighters is not enough to explain the group's success
- Bronk: Most ISIS fighters are armed with Soviet-era small arms, M16/M4 pattern rifles
- ISIS makes planning any battle against them uncertain, writes Bronk
- What air power cannot do is easily degrade or neutralize ISIS's core advantages, he says
Editor's note: Justin Bronk is a research analyst in the military sciences program at the Royal United Services Institute in London.Follow him on Twitter. The views expressed are solely those of the author.
(CNN) -- It is a question that the global community is seeking to understand as the crisis in Iraq and Syria deepens. How can such a numerically small force as ISIS, which calls itself the Islamic State, have taken control of vast swathes of Syria and Iraq, and how can it hold the ground taken while simultaneously conducting multiple offensive actions in both countries?
The most recent CIA estimate in September 2014 put the total number of ISIS fighters in Iraq and Syria at between 20,000 and 31,500. But such numbers, while alarming, are not nearly enough to explain the stunning military successes the group has enjoyed.
ISIS is at heart a guerrilla army that has recently captured large stocks of modern and heavy weaponry.
READ: Opinion: Will ISIS 'weaponize' foreign fighters?
While the equipment that makes headlines is war planes, captured tanks, heavy artillery and American-made Humvees, most ISIS fighters are still armed with the same mix of Soviet-era small arms and American M16/M4 pattern rifles that their Iraqi, Kurdish and Syrian opponents rely on.
Much of the heavy equipment ISIS has at its disposal was captured during their lightning advance into Iraq, not before. It is not the core reason for their battlefield successes. However, what it does do is make planning any battle against ISIS forces an uncertain exercise because one may have to face weapons and vehicles from right across the capability spectrum.
When it comes to offensives against prepared positions, ISIS forces can certainly deploy heavy artillery, modern weapons and tanks that give it greatly enhanced capabilities and completely outgun Kurdish Peshmerga forces in particular. Unconfirmed reports have suggested that ISIS even deployed a captured M1A1 Abrams in its takeover of the Mosul Dam, before eventually being driven back by repeated U.S. airstrikes.
This is where airpower can make a difference since heavy artillery, tanks and armoured vehicles are vulnerable to airstrikes when concentrated in the open such as at the Mosul Dam and in the current offensive to take Kobani.
What air power cannot do is easily degrade or neutralize ISIS's core advantages which are strong battlefield leadership, significant tactical autonomy and aggressive tactics. Their battlefield tactics are somewhat reminiscent of the German Blitzkrieg campaigns in the early part of World War II. They use fast, well-coordinated forces with vehicle support to attack enemy weak points in strength under the cover of long range artillery and mortar fire.
A particular speciality is outflanking defensive positions and then mopping up defenders who attempt to retreat. The tactic is as much psychological as it is kinetic, and is greatly magnified by the horrendous and public brutality ISIS has systematically exhibited wherever it has gained control.
二○一四年十月一十八日 - 更新0858 GMT（1658 HKT）
布朗克：大多數ISIS的戰士，手持蘇聯時代的小型武器，M16 / M4步槍圖案
而成為頭條新聞的裝備戰機，俘獲坦克，重砲和美國製造的悍馬，最ISIS戰機仍裝備有蘇聯時期的小武器和美國的M16 / M4模式相同的結構步槍，他們的伊拉克人，庫爾德人和敘利亞反對派依靠。
報告：ISIS有3架戰機 伊拉克武裝分子進行小的收益 ISIS推回Kobani