Ammon News - Beirut (Reuters) - Militants linked to al Qaeda in Syria killed a senior figure in the Western- and Arab-backed Free Syrian army on Thursday, an FSA source said, signaling a widening rift between Islamists and more moderate elements in the armed Syrian opposition.

Kamal Hamami, a member of the Free Syrian Army’s Supreme Military Council, known by his nom de guerre Abu Bassel al-Ladkani, 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, a Free Syrian Army 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,” Saadeddine added.

The Free Syrian Army 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.