BEIRUT – Tension has mounted between the Al-Nusra Front and Free Syrian Army-affiliated rebel alliance the Southern Front in Syria’s Quneitra region, which borders Israel.

The Southern Front issued a statement accusing the Al-Qaeda-linked militants of opening fire on one of their reconnaissance units in an unprovoked attack.

“On Monday, June 8, 2015, one of our groups in Quneitra was intentionally fired upon by Al-Nusra Front elements while observing the movements of the Assadist enemy,” the statement read.

“It should be noted that the assaulted group alerted [groups], including Al-Nusra Front elements, in the area to its movement,” the FSA-linked rebel coalition added.

“However, after receiving orders, the elements opened fire directly on [Southern Front affiliate Aasifat al-Haqq operations room's] group.”

The rebel coalition called on the Nusra perpetrators to be “transferred to a fair court” and held accountable for their action in the flashpoint region, where insurgents have battled regime forces backed by Hezbollah.

“If this assault is repeated by any actor against the operation room’s fighters or the Southern Front’s fighters we will respond in a decisive manner,” the statement added.

However, the Southern Front stressed that it was not seeking to fight Nusra in the region, saying it was “intent on not entering any secondary battle that serves no purpose other than to lengthen the life of the Assad regime.”

“The liberation of Syrian territory is a genuine task among the tasks of the Southern Front in general and the Aasifat al-Haqq operations room under the Southern Front.”

For its part, Nusra has not issued any official statement on the incident, while pro-rebel outlets have only carried the Southern Front statement and have yet to published any reports on the circumstances of the attack.

The alleged Nusra attack is the latest example of the tense relations between the Al-Qaeda-linked group and the Southern Front coalition that reportedly maintains close ties with foreign powers seeking to depose the Assad regime.

On April 13, the Southern Front officially cut ties with Nusra two weeks after both groups swept regime forces from the Nasib border crossing with Jordan.

“[We] reject any military or [ideological] cooperation or rapprochement with the Al-Nusra Front or any takfiri [ideology] adopted by any group among the ranks of the Syrian rebels,” read a joint statement issued by groups under the Southern Front’s command.

“[We] consider the Southern Front the only military [entity] representing the Syrian revolution in southern Syria.”

The statement was endorsed by the FSA’s First Army, the Swords of al-Sham Brigades, the Dawn of Islam Division, the Yarmouk Brigade and the 1st Brigade, all moderate fighting units that have reportedly received US-manufactured anti-tank weaponry.

Dubai-based Al Aan television reported that the move “came suddenly without any […] harsh disputes between the factions and the Al-Nusra Front.”

However, the network noted that Nusra and the Southern Front had previously butted heads in the Daraa al-Balad district of the provincial capital, as well as at the Nasib border crossing.

Despite the cut in ties, both sides reportedly fought together against the regime in its failed late April offensive on Busr al-Harir.