A car-bomb exploded in the centre of Damascus, just as the international mediator was in the Syrian capital trying to secure a ceasefire with President Bashar al-Assad.
It detonated near a police station in the Bab Touma district. Syrian state television reported several people were killed.
The UN/Arab League mediator Lakhdar Brahimi is trying to establish a truce in the civil war that erupted out of an uprising to overthrow Assad.
Brahimi wants it to coincide with the Islamic Eid al-Adha holiday at the end of the week.
At least 30,000 people are estimated to have been killed in the 19-month conflict.
After the meeting, the envoy told reporters: “If we get a temporary and effective truce, we will try to consolidate it. And if it doesn’t work, we hope that we will find a solution for the Syrian people.”
The state news agency said the government would support ‘any sincere effort to find a political solution to the crisis based on Syrian sovereignty and the rejection of foreign intervention.’ It added that proposals ‘must be centred around the principle of halting the terrorism’, which is the government’s word for rebel action.
The previous ceasefire brokered by Kofi Annan barely took effect before collapsing.