At least 18 Syrian government soldiers have died in a bomb blast near the capital, Damascus, state media say, in one of the deadliest attacks in months.
At least another 20 soldiers were injured when the bomb was detonated on an army bus on Thursday morning.
No group has yet said it was responsible.
Such attacks are relatively rare near Damascus, but there have been two similar blasts on buses transporting military personnel in the past year.
In February, one soldier was killed, while last October 14 people died in what was at the time the worst attack in the Syrian capital for four years.
In response, the government shelled a rebel-held town in the north-western Syria. Four children – who were walking to school – were among those killed in that attack.
The conflict has left about 500,000 people dead, devastated cities and drawn in other countries.
Millions of Syrians have been forced to flee their homes.
A peaceful uprising against the president of Syria 10 years ago turned into a full-scale civil war. The conflict has left half a million people dead, devastated cities and drawn in other countries.
Even before the conflict began, many Syrians were complaining about high unemployment, corruption and a lack of political freedom under President Bashar al-Assad, who succeeded his father, Hafez, after he died in 2000.
In March 2011, pro-democracy demonstrations erupted in the southern city of Deraa, inspired by uprisings in neighbouring countries against repressive rulers.
When the Syrian government used deadly force to crush the dissent, protests demanding the president’s resignation erupted nationwide.
The unrest spread and the crackdown intensified. Opposition supporters took up arms, first to defend themselves and later to rid their areas of security forces. Mr Assad vowed to crush what he called “foreign-backed terrorism”.
The violence rapidly escalated and the country descended into civil war. Hundreds of rebel groups sprung up and it did not take long for the conflict to become more than a battle between Syrians for or against Mr Assad. -BBC