WARNING: CONTAINS DISTURBING IMAGES
Bodies are carried away from the site of a blast in the Syrian capital Damascus.
State TV reports 40 were killed and 100 wounded when two booby-trapped cars blew up at security sites.
This is the worst violence to hit Syria's capital during nine months of unrest over the rule of President Bashar al-Assad.
Al Manar news channel described the attack as a suicide bombing and said initial inquiries indicated al Qaeda was behind it.
They say most of the casualties were civilians.
The attack comes a day after the arrival of Arab League officials to prepare for a monitoring team that will check whether Assad is implementing a plan to end the bloodshed.
The escalating violence on both sides has raised fears that the country is slipping towards civil war.
Lily Grimes, Reuters