Syrian forces killed at least 10 people on Saturday in a village north of Damascus where army defectors had taken refuge, and in the coastal province of Latakia the army clashed with rebel fighters, activists said.
Activist Omar Hamza said the Damascus killings occurred after a group of soldiers defected and were pursued by forces loyal to President Bashar Assad into the village of Bakha north of the capital.
Four rebels and six civilians were killed, Hamza said. The British-based Syrian Observatory for Human Rights also put the death toll at 10, but said they were all defectors.
The bloodshed was the latest incident to mar a two-week-old ceasefire agreement brokered by the United Nations, which is seeking a negotiated solution to the 13-month Syrian uprising, inspired by rebellions against authoritarian rule across the Arab world.
The United Nations says Syrian forces have killed 9,000 people since the start of the unrest. Syrian authorities blame foreign-backed militants for the violence and say 2,600 soldiers and police have been killed.
SANA, the official state news agency, said on Saturday a military unit had foiled a "terrorist attempt" to infiltrate the country from the Mediterranean, although it provided no further details.
UN Secretary-General Ban Ki-moon said on Thursday the Syrian government had not complied with commitments it made under the ceasefire plan, while Assad's government says rebels have flouted the deal.
In Latakia, the Observatory said soldiers and rebels were fighting in the village of Burj al-Salaam, close to the site of a presidential palace, but gave no further details.
Overnight, five members of the security forces were killed in an explosion targeting two vehicles between the towns of Moadamiya and Deraya in Damascus province, it added.
Meanwhile, gunmen in inflatable dinghies have attacked a Syrian military unit on the Mediterranean coast, leading to a fire-fight in which several people from both sides were killed, the SANA official news agency said on Saturday.
"The fighting resulted in the death and wounding of a number of military personnel while the number of those killed from the terrorist group was not known because they attacked the military unit at night," SANA said.
SANA did not mention the identity of the attackers. It said the fighting occurred 30 to 35 kilometers (19 to 22 miles) south of the border with Turkey.
Syria's government has consistently accused Turkey, which hosts the leadership of the rebel Free Syrian Army, of allowing weapons and funds to flow to insurgents fighting for the last 13 months for the overthrow of President Bashar Assad.
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