The ambush is the second this week to target buses traveling between government-controlled areas and to be blamed on suspected Daesh (ISIS or ISIL) terrorists against Syrian people and military.
In another attack on Wednesday nearly 40 people were killed and wounded, most of them were soldiers returning home for the holidays. Daesh militants were also believed to be behind that attack.
Sleeper cells of Daesh terrorists have been active in the desert area south and central Syria despite losing control in the country since last year.
The militants ambushed three buses traveling down a highway in central Syria, immediately killing nine and wounding four, according to the governor of the central Hama province, Mohammed Tarek Krishani.
Krishani told local media the passengers were traveling to the central Salamiyah town from the country's west in a three-bus convoy when they were attacked, he told state TV Al-Ikhbariyah.
Seven ambulances arrived on the scene, the governor said, adding that the rest of the passengers were sent to safety.
Syrian State TV quoted the head of the local hospital as saying that one of those killed was a 13-year-old girl.