Beirut: Key rebel group Ahrar Al Sham said on Wednesday it will not take part in peace talks in the Kazakh capital next week aimed at ending Syria’s nearly six-year-old war.

The announcement came as Russia and Turkey — which along with Iran organised the talks starting in Astana on Monday — carried out their first joint air strikes against Daesh in the war-torn country.

Ahrar Al Sham, which counts thousands of fighters in central and northern Syria, said it would not attend the Astana talks due to “the lack of implementation of the ceasefire” in force since December 30 and ongoing Russian air strikes over Syria.

The Islamist faction was among the signatories of the ceasefire deal that does not include Daesh and Fateh Al Sham, which changed its name from Al Nusra Front after breaking ties with Al Qaida.

The truce, brokered by regime supporter Russia and rebel backer Turkey, has largely held across Syria although fighting has persisted in some areas.

Ahrar Al Sham cited “the regime’s offensive against our people in Wadi Barada”, an area 15 kilometres northwest of Damascus that is the capital’s main source of water, among its reasons for staying away from the talks.

President Bashar Al Assad’s forces have pressed an assault to retake the area from rebels after mains supplies were cut last month, leaving 5.5 million people in Damascus and its suburbs without water.

Ahrar Al Sham said however that it would support decisions taken by other rebel groups represented at the Astana talks if they were “in the interest of the nation”.

Mohammad Alloush of the Jaish Al Islam (Army of Islam) faction will lead a “military delegation” in Astana of around eight people, backed by nine legal and political advisers from the High Negotiations Committee umbrella group.

Syria’s UN ambassador Bashar Al Jaafari is to head the government delegation.

Regime and rebel figures are headed for Kazakhstan with diametrically opposed approaches to the aims of the talks.

Damascus has insisted it will seek a “comprehensive” political solution to the conflict, while rebels say they will focus solely on reinforcing the frail nationwide truce.

Next week’s talks mark the first time since the conflict began in 2011 that the United States has not been at the centre of peace negotiations.

Iranian officials said on Wednesday they were strongly opposed to Washington joining the talks.

Turkey and Russia — which started air strikes in support of Al Assad’s regime in 2015 — have however said the new US administration of Donald Trump should be represented.