A suicide car bomb attack in southern Syria on Tuesday (July 10th) killed at least eight fighters, including Syrian regime and opposition forces, the Syrian Observatory for Human Rights said.

The explosion hit Zaizun, a village in the western countryside of Daraa province, which opposition fighters agreed in recent days to hand over to regime control, AFP reported.

"Eight regime and opposition fighters who recently reconciled were killed in a suicide car bomb attack targeting a military position in Zaizun," said Observatory head Rami Abdel Rahman.

No one immediately claimed responsibility for the attack, but the village lies near a sliver of southern territory controlled by Jaish Khalid ibn al-Walid, a faction linked to the "Islamic State of Iraq and Syria" (ISIS).

Abdel Rahman said it was "likely" that Jaish Khalid ibn al-Walid was responsible.

"This is the first suicide attack targeting regime forces since the beginning of their operations in Daraa," he said.

The regime is now in control of around 80% of Daraa province, while opposition fighters hold around 15%, according to the Observatory.

Jaish Khalid ibn al-Walid -- which is not included in the ceasefire deal -- controls the remaining sliver, where around 30,000 people live.