At least nine people, including seven Syrian government soldiers, were killed in an attack on a bus, a Britain-based war monitor said Sunday.
The ambush also wounded 16 people travelling in the vehicle from the northern city of Raqqa to the capital Damascus, said the Syrian Observatory for Human Rights (SOHR).
It is the second attack in less than a week to target a bus carrying soldiers "and probably some of their relatives", the director of SOHR, Rami Abdel Rahman, told AFP.
Two civilians also died in the assault, SOHR said.
However, Syria's official news agency Sana said the nine killed in the "terrorist attack" were all civilians.
No one has claimed responsibility for the attack.
Last month almost 40 soldiers, including eight officers, were killed in an ambush by Islamic State in the eastern Deir Ezzor province.
The terror group overran large parts of Syria and Iraq and proclaimed a cross-border "caliphate" in 2014, before multiple offensives in the two countries led to its territorial defeat.
The group was overcome in Syria in March last year, but sleeper cells continue to launch attacks.
More than 387,000 people have been killed and millions forced from their homes since Syria's civil war broke out in 2011.