The ambush is the second this week to target buses traveling between the regime-controlled areas and to be blamed on suspected Daesh militants.
At least nine people, including a 13-year-old girl, have been killed as militants ambushed buses traveling down a highway in central Syria.
The attack on late Sunday night is the second this week to target buses traveling between the regime-controlled areas and to be blamed on suspected Daesh militants.
Another attack earlier on Wednesday killed nearly 30 people, most of them soldiers returning home for the holidays. Daesh militants were believed to be behind that attack.
Daesh militants have been active in the desert area south and central Syria despite losing territorial control in the country since last year.
Local officials said Daesh militants were believed to behind the Sunday attack, which also targeted oil trucks, but they offered no details on how it was carried out.
The militants ambushed three buses traveling down a highway in central Syria, immediately killing nine and wounding four, according to the governor of the regime-controlled 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.
The convoy also included oil trucks, he told pro-regime TV Al-Ikhbariyah, without elaborating.
Seven ambulances arrived on the scene, the governor said, adding that the rest of the passengers were sent to safety.
Thirteen-year-old girl killed
The TV quoted the head of the local hospital as saying that one of those killed was a 13-year-old girl.
The Britain-based Syrian Observatory for Human Rights, a war monitor, said the attackers, suspected Daesh militants, targeted the buses traveling down the highway, killing two civilians and seven soldiers. The attack left 16 wounded, according to the Observatory.
The difference could not be immediately reconciled but state media rarely accounts for military casualties.
The regime media said the attack earlier this week was against civilians. But the Observatory said it targeted soldiers from the elite Fourth Division army unit returning home for the holidays.