In Damascus Syrian state run television showed the damage to the Central Bank after militants fired rocket propelled grenades at the building.
The attack came just hours after the much awaited arrival in the capital of the head of the UN observer mission.
Norwegian Major General Robert Mood has the job of overseeing the shaky truce which came into force nearly three weeks ago.
“I call on everyone to help us and to cooperate with us in this very challenging task ahead of us,” said Major General Mood.
There are now thirty unarmed UN monitors in Syria, in total 300 are planned.
Activists say violence in the city of Homs has dropped sharply since the observers deployed a permanent two-man team there last week.
Their presence allowed residents to retrieve three bodies that had previously been too risky to collect because of the threat of sniper fire.