The self-proclaimed Islamic State of Iraq and al-Sham (ISIS) has acknowledged for the first time that its fighters have been defeated in the Syrian town of Kobani and vowed to attack the town again.

In a video released by the pro-IS Aamaq News Agency late Friday, two fighters said the airstrikes by the U.S.-led coalition were the main reason why ISIS fighters were forced to withdraw from Kobani. One fighter vowed to defeat the main Kurdish militia in Syria, the People's Protection Units known as the YPG.

On last Monday, activists and Kurdish officials said the town was almost cleared of ISIS fighters, who once held nearly half of Kobani.

In the newly released ISIS video, the militant fighters acknowledged that they have been driven from the town.

"A while ago we retreated a bit from Ayn al-Islam because of the bombardment and the killing of some brothers," said one masked fighter, using the group's preferred name for Kobani. He spoke Arabic with a north African accent.

The failure to capture and hold Kobani was a major blow to the extremists. Their hopes for an easy victory dissolved into a costly siege under withering airstrikes by coalition forces and an assault by Kurdish militiamen.

The United States and several Arab allies have been striking ISIS positions in Syria since September 23. The campaign aims to push back the group after it took over about a third of Iraq and Syria and declared the captured territory a new caliphate.

Now Kurdish officials are hailing the retaking of Kobani as an important step toward rolling back the group's territorial gains.

"Kobani Canton is a representative of the resistance against terrorism in the world," said senior Syrian Kurdish official in Kobani, Anwar Muslim. "We hope that the world will support us to come through our struggle against ISIS."

Meanwhile the ISIS fighters vowed that their defeat in Kobani will not weaken them.

"The ISIS will stay. Say that to (U.S. President Barack) Obama," said the fighter, pointing his finger toward destruction on the edge of Kobani.

The fighters both laid blame for their defeat on the coalition air campaign, seemingly downplaying the role played by Kurdish militiamen whom they refer to as "rats."

Another ISIS fighter, also speaking in Arabic, said while standing on a road with a green sign with "Ayn al-Islam" sprayed on it: "The warplanes did not leave any construction. They destroyed everything, so we had to withdraw and the rats advanced."

"The warplanes were bombarding us night and day. They bombarded everything, even motorcycles," the fighter said.

ISIS launched an offensive on the Kobani region in mid-September capturing more than 300 Kurdish villages and parts of the town. As a result of the airstrikes and stiff Kurdish resistance, ISIS began retreating a few weeks ago, losing more than 1,000 fighters, according to activists.

More than 200,000 Kurds were forced from their homes, many of whom fled to Turkey.

Earlier this week, Kurdish officials said YPG fighters have launched a counterattack to retake some of the surrounding villages around Kobani, many of which remain in ISIS hands.