There are growing worries that the Syrian opposition may splinter, after top Free Syrian Army (FSA) commander Kamal Hamami was killed Thursday by Al Qaeda-linked militants in northern Syria. He was meeting with them so that the Sunni factions could coordinate moves against the Shiite-backed regime of Syrian ruler Bashar al-Assad.

The Islamists who killed Hamami, also known as Abu Bassel al-Ladkani, then phoned his colleagues to boast about the killing and threaten further ones:

“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 FSA is ready to go to war.

“We will not let them get away with it because they want to target us,” a senior FSA commander said on condition of anonymity after members of the Islamic State of Iraq and Levant killed Kamal Hamami on Thursday. “We are going to wipe the floor with them,” he said. Hamami, also known by his nom de guerre, Abu Bassir al-Ladkani, is one of the top 30 figures on the FSA’s Supreme Military Command. His killing highlights how the West’s vision of a future, democratic Syria is unravelling.

The FSA reportedly issued a one-day ultimatum for Al Qaeda to hand over the killers. The assassination will deepen concerns both about the political cohesion of the Syrian opposition as a whole, and about the degree to which Western nations that seek to bolster the rebels can ensure that lethal and non-lethal assistance is not seized by extremists.

Syrian armed forces backed by Hezbollah troops have recently made significant progress in retaking territory from the opposition, seizing the strategic city of Qusayr and capturing rebel-controlled neighborhoods in Homs.

[Photo: FreedomHouse / Flickr]