The government newspaper Tishrin reported Monday that Syrian security officials believe the booby-trapped car was brought into Syrian territory a day before the attack through the country's border with a neighboring Arab state. The paper did not mention the name of the other country.
According to the report, one person was driving the vehicle, and efforts are now being made to complete his identification through DNA tests.
A number of radical Islam activists were arrested after the explosion. The Tishrin report indicates that Islamic elements outside Syria were behind the attack which shocked the country and followed a series of assassinations on Syrian soil.
Syrian papers on Sunday hinted at foreign involvement in the car bombing. So far, no organization has claimed responsibility for the attack and the Syrian government has refrained from clearly pointing the finger at anyone.
Saturday's 200 kilogram car bomb near a Syrian security complex on the southern outskirts of the capital was the biggest – and deadliest – attack to occur in the country since the 1980s when authorities fought an uprising by Muslim militants.
The government-owned daily al-Thawra claimed in an editorial Sunday that recent attacks in Syria were planned outside the country, but did not mention any names.
However, the comment came a week after Syria massed thousands of troops north of its borders with neighboring Lebanon. Syria says the deployment is meant to curb smuggling, but President Bashar Assad has warned recently that "extremist forces" were operating in northern Lebanon and destabilizing his country.
Tishrin said the bombing was carried out by some parties it said were angered by Syria's "victorious return to the international arena after the desperate attempts to isolate, besiege and punish it."
The Associated Press contributed to this report