A pledge signed by nine al-Qaida commanders from Afghanistan, Turkmenistan and Iran is the latest example of how the terrorist movement's once monolithic structure has begun to crumble under stress from Syria's civil war.

The "Khorasan pledge," which was signed April 9, announces a shift in loyalty from al-Qaida chief Ayman al-Zawahiri to Abu Bakr al-Baghdadi, head of the Islamic State of Iraq and Syria (ISIS).

Al-Zawahiri denounced ISIS at the beginning of February and said al-Qaida had nothing to do with the group. The split left al-Qaida without representation in Iraq, where the ISIS began and spent the better part of the past decade fighting U.S. troops.

ISIS had been engaged in an internecine battle with Jabhat al-Nusra, al-Qaida's other Syrian branch prior to al-Zawahiri's denunciation.

The nine leaders who signed the pledge attacked Zawahiri and Jabhat al-Nusra without naming them, saying they "did not have any courage to enforce judgments over those who disobey sharia, under the pretext of avoiding a clash with people due to their inability and incapacity, although they enforced in secret more than they did out in the open."

They argued that conflict began with a dispute between the late Islamic State of Iraq leader Abu Musab al-Zarqawi and Zawahiri in 2005. In their view, Zawahiri has "always been lax." Zawahiri is an apostate who does not go far enough in merely referring to the Shia as infidels, they said.

The declaration has been circulating in jihadi forums such as Shumukh al-Islam.

One source sought to downplay the pledge's importance, telling the Lebanese Al-Akhbar newspaper that it had been blown out of proportion by the media. "The people mentioned are not in a leadership position and do not carry any notable responsibilities," the source told Al-Akhbar.

ISIS spokesman Mohammed al-Adnani attacked al-Qaida a few days after the signing of the declaration saying that "al-Qaida deviated from the rightful course."