BEIRUT — Al-Qaida's leader has reportedly annulled a merger between the Syrian and the Iraqi branches of the terror network, just two months after they joined forces.

The Qatar-based Al-Jazeera TV says Ayman al-Zawahiri also urged leaders of Iraq's affiliate and the Nusra Front in Syria to end disagreements and "stop any verbal or actual attacks against one another."

It says al-Zawahiri's call came in a letter to the station posted late Sunday. The Britain-based Syrian Observatory for Human Rights, which has activists in Syria, says it also acquired a copy of the letter.

The authenticity of the statement could not be independently verified.

Al-Zawahiri's appeal appears aimed at containing rising tensions between the two factions. The Syrian branch is the most powerful rebel force fighting to topple President Bashar al-Assad.