Fighters from the Islamic State in Iraq and t
Fighters from the Islamic State in Iraq and t Reuters

The Al-Qaeda-affiliated group the Islamic State of Iraq and the Levant (ISIS) on Tuesday urged its fighters to “crush” other rebel groups in Syria, in an audio message from the group’s spokesman quoted by Al Arabiya.

The spokesman, Abu Mohammad al-Adnani, reportedly called on ISIS fighters in Syria to “crush them (the rebels) totally and kill the conspiracy at birth,” warning opposition fighters that “none of you will remain, and we will make of you an example to all those who think of following the same path.”

The threat came as Syria’s “second civil war” between moderate and jihadist rebels continued to claim lives.

In recent days, several groups of Syrian rebels united for the purpose of launching a new “revolution” against ISIS, which is part of a group of jihadist rebels that declared Aleppo to be an independent Islamist state and have summarily executed members of the Western-backed rebel groups.

The fighting between rebels killed at least 50 Syrian rebels on Sunday alone.

On Wednesday, Syrian Islamist rebels from the Islamic Front said they had captured a key Al-Qaeda base in Aleppo.

According to the Syrian Observatory for Human Rights, fighters found the bodies of several men who had apparently been executed, along with dozens of prisoners kept at a hospital in the Qadi Askar district. The hospital was being used as ISIS headquarters.

Meanwhile, Al Arabiya reported, the moderate rebels have found an ally in a rival Al-Qaeda group which said it has joined forces with other rebel groups in fighting ISIS.

Al-Nusra Front leader Abu Mohammad al-Golani said in an audio recording that “high-level” fighting erupted between his group and ISIS on Tuesday.

He blamed the fighting on what he said were “mistakes” made by ISIS, such as the arrest of a Nusra commander in Raqqa.

In his message, Golani urged all rebel groups to unite against President Bashar Al-Assad regime.

“This unfortunate situation prompted us to make this initiative to save the ground from loss. This initiative calls for the formation of a legitimate committee from all recognized factions with an independent leadership,” he said, according to Al Arabiya.

Golani also noted that all infighting in the groups must end and an exchange of prisoners should take place, adding that rebels should focus their efforts on fighting Assad’s forces and not fighting each other.

Al Arabiya noted that divisions within Al-Qaeda appeared in November 2013, when Al-Qaeda chief Ayman al-Zawahiri appointed Al-Nusra Front jihadists to carry the network’s banner in Syria and ordered ISIS to disband.

Zawahiri’s remarks confirmed a written order issued in June that has so far gone unheeded.

Zawahiri said that Al-Nusra Front was the jihadist group’s only branch in Syria, tasked with reporting “to the general command,” and will no longer operate under the banner of Al-Qaeda’s Iraq affiliate.

In April 2013, a dispute erupted when ISIS leader Abu Bakr al-Baghdadi had claimed that Nusra was now its branch in Syria, but that was rejected by Nusra commander Golani, who affirmed his allegiance to Zawahiri.

The Al-Nusra Front, created in January 2012, joined Al-Qaeda in December of that year and is on a U.S. list of foreign terrorist organizations.