BEIRUT -- Clashes between two extremist factions in northwestern Syria left dozens of fighters dead on both sides and raised fears of more deadly violence between groups battling President Bashar Assad's troops ahead of U.N.-brokered peace talks later this month, activist and insurgents said Tuesday.

The fighting between the al Qaeda-led coalition known as the Levant Liberation Committee and the extremist Jund al-Aqsa group left nearly 70 fighters dead in some of the deadliest clashes between insurgents in years, an opposition monitoring group and a rebel commander said.

The fighting centred in areas where the central province of Hama and the northwestern province of Idlib meet, they said.

A Syrian rebel commander speaking from Turkey said Jund al-Aqsa has proven recently that it is a branch of the Islamic State group that is the arch-rival of al Qaeda's Fatah al-Sham Front. The commander, who spoke on condition of anonymity for fear of reprisals, said Jund al-Aqsa fighters stormed several areas controlled by the Levant Liberation Committee and killed some of its members triggering intense fighting as of Monday.

"There is no solution but to uproot Jund al-Aqsa," the commander said by telephone.

The Britain-based Syrian Observatory for Human Rights, which tracks Syria's war, reported that the Levant Liberation Committee has captured six villages from Jund al-Aqsa so far.

The Observatory said two days of fighting has left 69 fighters dead, including 39 from the Levant Liberation Committee. It said the 30 dead from Jund al-Aqsa includes four suicide attackers who blew up vehicles that they were driving.

Abdul-Rahim Attoun, a senior al Qaeda religious official in Syria, blamed in an audio released late Monday Jund al-Aqsa for being a group that paid allegiance to IS. He added that Jund al-Aqsa was blocking roads used by the Levant Liberation Committee to attack government forces.

A Jund al-Aqsa commander who goes by the name of Karmo told The Associated Press that the fighting was triggered by Levant Liberation Committee attacks on Jund al-Aqsa positions.

In the southern city of Daraa, where clashes between insurgents and government forces have continued for days, opposition activist Ahmad al-Masalmeh said an air raid hit a hospital in the city, putting it out of service. The Observatory's chief Rami Abdurrahman said there were reports of a hospital being and they were still working on confirmation.

The fighting came as a state-run newspaper said in an editorial that a meeting between the Syrian government and opposition in Kazakhstan this week will not be "fruitful" unless they are focused on fighting terrorism.

The two-day conference in Astana that begins Wednesday is aimed at strengthening a Dec. 30 cease-fire. The government has long referred to all those fighting against it, including mainstream rebels, as "terrorists."

An editorial in Al-Baath daily of President Bashar Assad's ruling Baath party said "without fighting terrorism and defeating terrorists, any solution will not be fruitful."

The cease-fire excludes al Qaeda branch Fatah al-Sham Front and the Islamic State group.

Iran's deputy foreign minister in charge of Arab countries Hossein Jaberi Ansari told state TV that a ceasefire and reconciliation in Syria are on the agenda in the Astana talks.

"Consolidation of the ceasefire, inspecting cases of violation and finalization of regulations for monitoring of the ceasefire will be carried out in the talks," said Ansari upon arrival in Astana. "Political issues related to the trend of reconciliation in Syria are on the agenda in Astana."

Astana hosted a round of talks among the main Syrian players last month. A new round of U.N.-brokered peace talks for Syria is scheduled for Feb. 23. Several previous attempts to end the civil war, which began nearly six years ago, have failed.

In Damascus, the U.N. Resident and Humanitarian Coordinator for Syria appealed to all parties to reach an agreement for immediate access to the besieged villages of Zabadani, Madaya, Foua and Kfarya, adding that aid has not reached these areas since Nov. 28.

Ali Al-Za'tari said in a statement that "the situation is a looming humanitarian catastrophe." He added that 60,000 "innocent people" live in these areas.

Syrian rebels have been laying siege Foua and Kfaraya in the northwestern province for years while government forces have besieged the mountain resorts of Zabadani and Madaya near the border with Lebanon.