The spokesman of the advance team of UN observers said the group visited two central regions and established contacts with all parties there on Sunday.
Briefing reporters in the capital Damascus late Sunday, Neeraj Singh said the team visited Hama province and Rastan town near flashpoint Homs province.
The spokesman, who is an Indian national, refused to give further details on the observers' activities because "the precise details are premature to talk about."
Singh went on to say that the team is preparing for the arrival and deployment of more observers.
A day earlier, the UN Security Council unanimously decided to approve the deployment to Syria of up to 300 unarmed UN military observers in order to monitor a fragile ceasefire between the Syrian government forces and opposition fighters.
The task assigned to the UN observers, Singh said, is to establish liaison with all parties in the conflict-torn country and make logistic arrangements.
On the ground, seven unarmed military observers are already in place, two of whom were dispatched to Homs on Saturday. Many more are expected to arrive in Syria by next week.
The advance team of international observers arrived last week after Syria accepted the UN-backed truce aiming to solve the crisis politically.
Since their arrival, violence has to some extent declined; however, attacks and deaths are reported to be taking place on a daily basis.