The UN's stabilisation mission in Syria has been suspended due to escalating violence.
The chief of UNSMIS General Roger Mood said: "The observers will not be conducting patrols and will stay in their locations until further notice."
The move comes after overnight violence in the country.
Seven people were killed in Douma, and at least 18 others died in clashes elsewhere in Syria.
On Friday General Mood held a news conference in Damascus and said that there appeared to be a "lack of willingness to seek a peaceful transition".
He added: "Instead there appears to be a push towards advancing military positions".
At least 10,000 people have died since pro-democracy protests began in March 2011, according to the UN.