A dozen Syrian opposition factions have suspended talks on new peace negotiations, accusing the regime of violating a four-day-old ceasefire with attacks near Damascus that continued Tuesday (January 3rd), AFP reported.

The decision threatens the process sponsored by Russia and Turkey, which began with a truce and is meant to lead to negotiations in the Kazakh capital Astana this month.

The ceasefire has brought quiet to large parts of the country but has been undermined by sporadic violence, particularly fighting in the Wadi Barada region north of Damascus that supplies the capital's water.

Regime forces backed by fighters from Lebanon's Hizbullah have continued to press a two-week-old offensive in Wadi Barada despite the ceasefire which began December 30th.

A dozen opposition groups announced in a statement late Monday the "freezing of all discussion linked to the Astana negotiations".

They said they had adhered to the ceasefire, but accused the regime of "major and frequent violations, notably in the regions of Wadi Barada and Eastern Ghouta" near Damascus.

The fighting in Wadi Barada continued Tuesday, the Syrian Observatory for Human Rights said, with regime forces attacking with helicopters and artillery fire after advancing on Monday to the outskirts of the Ain al-Fijeh spring.