The ceasefire in Syria "is about to collapse," an official from the opposition said in an interview published Sunday, just days before the resumption of peace talks in Geneva.

The ceasefire in Syria "is about to collapse," an official from the opposition said in an interview published Sunday, just days before the resumption of peace talks in Geneva.

"Over the last 10 days we have seen a very serious deterioration and the ceasefire is about to collapse," Bassma Kodmani, a member of the High Negotiations Committee of the Syrian opposition, told Journal du Dimanche".

"The US-Russian mission monitoring the ceasefire is powerless," she told the French newspaper.

A ceasefire between the Syrian army supported by Russian air strikes and the allied forces brokered by the United States and Russia has largely held since February 27.

The truce does not include areas where the so-called 'Islamic State of Iraq and the Levant' (ISIL) takfiri group and Al-Qaeda's local affiliate Al-Nusra Front are present.

"A blow was dealt to the opposition, for sure," Kodmani admitted, adding Russia had "attacked the supply lines of the brigades of the moderate opposition on the ground until the cessation of hostilities intervened in February".

She said the withdrawal of Russian forces announced mid-March "indicates to those who support Bashar Al-Assad that this assistance will not be unlimited and unconditional."

"The challenge is whether Russia will be able to dictate the terms of negotiations with Damascus," she said.

The Geneva talks aimed at ending the global war on Syria are scheduled to resume on April 13.

The UN Security Council passed a resolution in December which paved the way for the Geneva talks and called for elections in Syria to be held 18 months after a transitional government is agreed.