The head of the United Nations’ Stabilisation Mission in Syria says the operation has been suspended because of escalating violence.
Norwegian General Robert Mood says the observers will cease patrols and stay in their current locations until further notice.
But he says the mission remains committed to ending the violence.
The announcement comes a day after General Mood had warned that the escalation in violence was limiting the observers' ability to do their work.
One British observer group reports that at least seven people were killed overnight in Douma, a suburban town east of the capital, while at least 18 others died in violence elsewhere.