-Analysis-

To win back Mosul, the Iraqi armed forces paid with their blood. But the difficult victory — obtained with the help of the international coalition — also marks a rebirth. Against all odds, the Iraqi army, federal police and anti-terror units have all been successfully rebuilt.

Back in 2014, the Iraqi troops had fallen back rather pitifully in Ramadi, Fallujah and Mosul in the face of a blitzkrieg by the Islamic State, or ISIS. Three years later, the same forces — but tougher — managed to retake the group's "capital," even though the numbers were not necessarily in their favor. Some 100,000 men were recruited to cordon off the city, but only 20,000 actually took part in the fighting inside Mosul, against about 5,000 jihadists, a ratio of one defender to four attackers. In urban fighting, the ratio should generally be at least one to six, sometimes even one to 10, in order to win.

The boldness of the Iraqi armed forces was particularly evident when they breached the defenses of ISIS on the eastern bank of the Tigris after having surrounded the city (which in 2009 had nearly three million inhabitants) last November. The clearing phase now underway on the river's west bank will continue for some time, as troops sweep building after building, looking for booby traps and possible remaining isolated fighters.

All eyes are now on Raqqa.

The battle of Mosul, which lasted close to nine months, will remain emblematic of urban warfare. Like the shorter battle of Stalingrad in 1942-1943 (six-and-a-half-months), considered the "mother" of urban battles, Madrid (1936), or Hué, in Vietnam (1968), the battle of Mosul will be carefully studied in war academies. It brought together, like rarely before, traditional war methods and high technology, basic tactics and operational innovations. Because cities have become crucial in asymmetric warfare, urban areas represent the "ultimate battlefield," as French army officials Frédéric Chamaud and Pierre Santoni write in their recent book.

In Mosul, the Iraqi armed forces also rediscovered some urban warfare "classics," such as frontline defense, capturing anchor points, snipers, booby traps and house to house warfare. But at the same time, they have had to face new challenges that are sure to leave their mark on future fighting, such as the use of drones coupled with suicide vehicles, already used by ISIS in the battles of Ramadi (February 2016) and Fallujah (June 2016), though on a lesser scale. Not to mention the underground tunnels.

All eyes are now on Raqqa, ISIS" stronghold in Syria, where some 2,500 jihadists are entrenched. In early June, breaches in the city's fortifications enabled the Syrian Democratic Forces to gain control of several districts, with heavy support from the Americans.

Raqqa is a smaller urban battlefield than Mosul (an estimated 100,000 civilians remain in the Syrian city, down from 220,000 in 2012), and ISIS is using the same combat methods with the same forceful resistance.

But the lessons from Mosul cannot be directly transposed to Raqqa. With the battlefield's confined space and narrow alleyways (making air support extremely difficult), along with an unknown level of preparation and motivation of the Syrian Democratic Forces and an extremely determined defense, it would be unwise to venture a prediction of when ISIS will be defeated in its Syrian stronghold.