ISIS fighters say constant airstrikes drove them out of Kobani

 Two purported ISIS fighters interviewed for a news agency working in ISIS-held territory have given the same reason for the militants' retreat from the Syrian city of Kobani: the constant pummeling by coalition airstrikes.

On Monday, Kurdish fighters declared that they had released the city on the border to Turkey from ISIS' grip after 112 days of fighting.

The efforts of the Kurdish fighters -- known as the YPG, or People's Protection Units -- on the ground were backed by an extensive campaign of airstrikes by the U.S.-led international coalition against ISIS.

And according to the interviews given to ISIS aligned Amak news agency in Syria, it was those airstrikes that won the battle for Kobani, referred to by the fighters as Ayn Al-Islam.

"Recently, we have withdrawn from Ayn Al-Islam bit by bit, because of the airstrikes and deaths of a number of our brothers," said one of the two fighters, his face covered apart from his eyes.

He points to a scene of destruction behind him but vows that ISIS will persist, "and this is the message we send to Obama."

ISIS launches assault on Iraqi city of Kirkuk 02:27

The second fighter, interviewed by Amak stood near a road sign reading Ayn Al-Islam. He said ISIS forces had raided 360 villages around Kobani, from which the defenders "ran away like rats."

But the reason behind their withdrawal from the city, he said, "is that we no longer had places to hold there. We were inside Ayn Al-Islam and we occupied more than 70%, but the airstrikes did not leave any building standing, they destroyed everything."

His horror of the airstrikes was apparent.

"I swear by God, their planes did not leave the air, day and night; they did airstrikes all day and night. They targeted everything. They even attacked vehicles; they have not left a building standing."

ISIS assault on Kirkuk

ISIS is on its heels after the loss of Kobani and an offensive by Kurdish Peshmerga -- armed fighters who protect Iraq's Kurdish region -- around Mosul, Iraq's second-largest city and a focal point for all sides in the conflict.

But on Friday, the Sunni extremist group launched an assault on Iraq's oil-rich city of Kirkuk in what may be an attempt to divert Kurdish troops from Mosul.

A report by Rudaw, a private website dedicated to presenting news from a Kurdish perspective, said at least 30 ISIS fighters were killed in the assault and 15 captured.

Casualties on the other side included Brig. Gen. Shirko Fateh, the highest-ranking operational commander of the Peshmerga brigade located in Kirkuk.

Deaths in Kobani

According to the Syrian Observatory for Human Rights, a London-based opposition group, from October 6 to Monday the fighting for Kobani killed 979 ISIS combatants, 324 YPG fighters and 12 rebels backing the YPG.

Thirty-eight more ISIS militants died in attacks using booby-trapped vehicles or bomb belts, and the ISIS shelling of Kobani killed 12 civilians, SOHR said.

"On the other hand, hundreds of (ISIS) militants died during U.S. and Arab allies' airstrikes on the city and its countryside," the group said.

However, the success of the coalition airstrikes in Kobani will be hard to replicate elsewhere.

There are almost no civilians left in the city of Kobani, and most residents left early on when the fighting started, especially in the contested areas close to the frontline.

This meant airstrikes were fairly straightforward, with the coalition able to target one side and avoid civilian casualties. The frontline was well defined, so it was clear where the ISIS and Kurdish fighters were.

A more challenging situation is when airstrikes seek to target ISIS inside populated areas like Mosul in Iraq, Raqqa in Syria and other cities under ISIS control.

Here the effectiveness of airstrikes is limited because of the risk of casualties among civilians. When coalition airstrikes hit cities in Aleppo, in northern Syria, civilian deaths were reported last year.

CNN's Brian Walker contributed to this report.