AMMAN // The deadline to resolve a dispute that brought the Free Syrian Army and Jabhat Al Nusra to the brink of war in southern Syria expired on Monday without resolution.

Conditions in southern Syria were tense on Monday night but it appeared as though moderate FSA factions had backed off from earlier threats to turn their weapons against the Al Qaeda-affiliated group.

A week of talks in northern Jordan involving rebel commanders, independent mediators and opposition judges ended without agreement late on Sunday and, on Monday morning, a group of 60 FSA units issued a statement saying they had ceased cooperating with Al Nusra in military operations.

However, FSA commanders, who had warned that the previously unified southern front in the uprising against Bashar Al Assad was dangerously close to collapsing into the kind of rebel infighting that has plagued the northern and eastern fronts, appear to have decided they are not prepared to risk such fratricidal violence.

Earlier in the week, FSA leaders said they would use force to free Ahmed Nehmeh, a senior FSA officer captured by Al Nusra last Saturday.

A source close to Al Nusra said it was sure the FSA was not prepared to open hostilities over Col Nehmeh.

“Those of us operating in the field all know what Al Nusra offered in order to get rid of Bashar,” the source said. “Therefore, having a war between Al Nusra and the FSA is not something that will happen easily.”

The FSA’s statement said cooperation between the two in Deraa would halt immediately, however.

That is likely to have significant implications for rebel effectiveness on the southern front. While Al Nusra has fewer men than the FSA, rebels say it is well equipped and admit it has played a decisive role in taking over regime positions, often breaking through stubborn defences using suicide bombs.

The dispute will also hit Al Nusra’s ability to operate effectively, and take pressure off regime forces, according to activists and rebels from Deraa, who said both had gained from working together.

“Al Nusra cannot carry out military operations on its own, and it needs the FSA,” said one activist.

The FSA statement, issued by its command for the southern front, was signed by its major factions, including the powerful Yarmouk Brigade, a unit commanded by Bashar Al Zaubi.

Mr Al Zaubi has had a fraught relationship with Col Nehmeh, and has previously called for Col Nehmeh’s arrest and punishment over a disastrous rebel defeat in the strategic town of Khirbet Ghazaleh last May.

There has been speculation among rebels in southern Syria that the Yarmouk Brigade was complicit in Col Nehmeh’s capture by Al Nusra, with Mr Al Zaubi cooperating with the Al Qaeda faction to settle that old score.

In addition, the FSA also said Al Nusra had no jurisdiction over FSA officers or fighters and had no right to detain or interrogate any of its members. A long-standing deal between Al Nusra and the FSA had ensured each stayed out of the other’s internal affairs.

“We have decided to cease cooperation with Al Nusra,” a senior commander based in Deraa said Tuesday, when asked if they were prepared to go to war with them. “We do not want any discord in the south and we do not want to have a repeated scenario like the North.”

Tensions have been running high since Al Nusra seized Col Nehmeh and, on Thursday, captured another FSA commander, Zuhair Dabo, following clashes in the town of Nawa.

In that incident, an Al Nusra leader, known as Emir Sharei, was killed, together with at least one FSA fighter.

Col Nehmeh is commander of Deraa Military Council (DMC), a link in the FSA’s chain of command between units on the ground and their headquarters in Turkey. He is also a key liaison between western and Gulf backers of the rebels and fighting units, and has close contacts with Jordanian and western intelligence agencies.

Following Col Nehmeh’s capture on Saturday, a film showing him battered and bruised after a violent interrogation was posted on YouTube. The video showed him confessing to helping foreign intelligence agencies undermine the war effort against the regime.

Al Nusra want Col Nehmeh to stand trial over the Khirbet Ghazaleh defeat, saying he helped orchestrate the debacle.

FSA units have also criticised Col Nehmeh over the incident and have agreed he should face down charges against him. But they want a neutral court, containing representatives from all factions.

psands@thenational.ae