Updated

A group of Syrian rebel groups say they are suspending talks about planned peace negotiations to be held later this month, because of what they describe as ongoing government violations of a four-day old cease-fire deal.

The cease-fire deal brokered by Russia and Turkey is to be followed by talks between mainstream rebel factions and government representatives in the Kazakh capital of Astana.

But in a statement posted late Monday, 10 rebel factions said they are suspending any talks related to the Astana negotiations or any discussions related to the cease-fire "until it is fully implemented." They include the powerful Army of Islam group which operates mainly outside the Syrian capital.

Opposition factions are angered in particular about an ongoing military offensive in the water-rich Barada Valley northwest of Damascus.