The Free Syrian Army’s Supreme Military Council will meet on Friday following the killing of a rebel FSA official, Mohammed Kamal al-Hamami.

An al-Qaeda-linked organization killed Hamami in Syria, highlighting the rift between Islamists and moderates in Syria’s armed opposition.

Hamami – also known as Abu Bassel al-Ladkani – was a member of the FSA’s Supreme Military Council.

The FSA official was meeting with members of the Islamic State of Iraq and the Levant in the port city of Latakia when they killed him, Qassem Saadeddine – an FSA spokesman – told Reuters.

“The Islamic State phoned me saying that they killed Abu Bassel and that they will kill all of the Supreme Military Council,” Saadeddine said from Syria. “He met them to discuss battle plans.”

This was not the first time that Islamists opposing Assad and other more moderate opposition forces have had disagreements, the Syrian Observatory's for Human Rights leader Rami Abdelrahman told AFP.

"Last Friday, the Islamic State killed an FSA rebel in Idlib province and cut his head off. There have been attacks in many provinces," he said.

FSA’s high-ranking officials will meet on Friday to discuss the killing of Hamami, said Louay Almokdad, an FSA spokesman.

“We must take the necessary measures on all levels, and the Islamic State of Iraq and the Levant brigades should hand us over those who killed Hamami… so we can hold them accountable,” Almokdad told Al Arabiya. “Chief of Staff of the Supreme Military Council of the FSA, Brigadier General Salim Idris, mourns our hero and martyr Mohammed Kamal al-Hamami, who was assassinated by the forces of evil.”

The FSA has been trying to build a network of logistics and reinforce its presence across Syria as the U.S. administration pledged to send weapons to the group after it concluded that Syrian President Bashar al-Assad’s forces had used chemical weapons against rebel fighters.

U.S. congressional committees are holding up the plan because of fears that such deliveries will not be decisive and the arms might end up in the hands of Islamist militants, security sources have said.

While Free Syrian Army units sometimes fight alongside Islamist militant groups such as the Islamist State, rivalries have increased and al-Qaeda-linked groups have been blamed for several assassinations of commanders of moderate rebel units.