A powerful blast killed 10 members of the security forces in the southern Syrian region of Quneitra on Friday, state television reported, blaming the explosion on "terrorists."
"An armed terrorist group detonated a 100-kilogramme (220-pound) bomb in Sahm al-Jolan in the region of Quneitra, killing 10 members of the security forces," the channel said.
The state run SANA news agency said the bomb was detonated by remote control and targeted a bus transporting government troops.
Quneitra is near the demarcation line with Israel, in the disputed Golan Heights.
A similar bomb attack in the town of Karak, in southern Daraa province, killed five soldiers, SANA said, also blaming "armed terrorist groups."
Three more soldiers were killed in separate incidents elsewhere, according to state media.
"Armed terrorist groups are pursuing their terrorist attacks against civilians and security forces as well as private and public property in violation of the plan by envoy Kofi Annan," SANA said.
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It was referring to a six-point plan drawn up by UN-Arab League envoy Kofi Annan in a bid to halt 13 months of violence that the United Nations says has left more than 9,000 people dead.
Meanwhile, the Syrian Observatory of Human Rights said 13 civilians were killed on Friday across the country.
It said regime forces killed an activist in Idlib, two civilians in Damascus and one in Aleppo and another in a bomb blast in the same region.
Five civilians were also killed in the shelling of neighbourhoods in Homs in central Syria, while gunfire and explosions were also heard in Qusayr near Homs, where the Observatory reported three civilian deaths.
"The mortars and rockets have not stopped in the night and are ongoing" in Homs, said activist Hadi Abdullah in Homs.
Friday's violence came as the international community seeks to pressure the Syrian regime to implement a ceasefire that went into effect on April 12 in accordance with Annan's plan.
The truce has been severely tested since then, with violence and casualties reported across the strife-torn country every day.
More than 120 people have died since April 12, according to a monitoring group.