Forty four people were killed and several others injured when a predominantly Kurdish town in northern Syria was hit by twin bombings on 27 July.
The Islamic State group has claimed responsibility for the attack.
According to reports, a truck loaded with large quantities of explosives blew up on the western edge of the town of Qamishli, followed by an explosives-packed motorcycle a few minutes later in the same area.
The blasts caused massive damage in the area and rescue teams were working to recover victims from under the rubble, the SANA news agency said.
Qamishli, near the Turkish border, is mainly controlled by Kurds but Syrian government forces control the town's airport. Syrian state TV broadcast footage showed people running away from smoke rising over the town and others running amid wrecked or burnt cars.
Qamishli resident Suleiman Youssef, a writer, told The Associated Press that he heard the first explosion from a few miles away. He said the blasts leveled several buildings to the ground and many people were trapped under the rubble.
"Most of the buildings at the scene of the explosion have been heavily damaged because of the strength of the blast," he said.
The Islamic State group, in a statement published by the IS-linked Aamaq news agency, said it carried out the attack in Qamishli, describing it as a truck bombing that struck a complex of Kurdish offices. The extremist group has carried out several bombings in Kurdish areas in Syria in the past.
The predominantly Kurdish US-backed Syria Democratic Forces have been the main force fighting IS in northern Syria, capturing significant territory from the extremists over the past two years. Today's explosion came as US-backed Kurdish forces pressed ahead with their offensive to take the IS-held town of Manbij, also in northern Syria but further to the east of Qamishli.