Russia has asked the United Nations to blacklist two major Syrian rebel groups, one of which is playing a key role in talks to end the conflict.

Vitaly Churkin, the country's ambassador to the UN, on Tuesday asked the world body to list Jaish al-Islam and Ahrar al-Sham, on a blacklist that includes the al-Nusra Front and the Islamic State of Iraq and the Levant (ISIL) group.

Mohammed Alloush, a leading figure in Jaish al-Islam (Army of Islam), is the chief negotiator for the High Negotiations Committee (HNC), the war-torn country's main opposition group, at UN-brokered peace talks in Geneva.

Churkin said that the two groups are "closely linked to terrorist organisations, primarily ISIL and al-Qaeda". 

The groups "both give [ISIL and al-Nusra] and receive from them financial, material, technical and military support," he said.

Both Jaish al-Islam and Ahrar al-Sham have fought alongside the al-Nusra Front against Assad forces but all are at war with ISIL (also known as ISIS).

Russian 'massacres'

Alloush rejected the accusation and said Russia was committing "massacres" with its air and artillery strikes in support of Assad.

"Russia supports it [the regime] with its weapons and airplanes and has committed 167 massacres in my country. The terrorist is the one who commits massacres, not the one who defends himself," he told the AFP news agency.

An unprecedented ceasefire in February brokered by Moscow and Washington saw Syria's government and rebel groups agree to halt attacks while pursuing peace talks.

However the HNC pulled out last week from the latest round of talks that began on April 13 in frustration over a spike in violence on the ground.

Russian Foreign Minister Sergey Lavrov angrily accused the HNC's members of throwing "tantrums".

The Jaish al-Islam rebel group is the most important in Damascus province, and Ahrar al-Sham is among the most powerful rebel groups in Syria.

The Damascus regime has consistently branded all of its opponents - armed or not - "terrorists" since the outbreak of war in 2011.

Source: Al Jazeera And Agencies