The tally included 2,923 government soldiers and 7,494 militant fighters, mainly from Islamic State and the al-Qaeda group Jabhat Fatah al-Sham, previously known as al-Nusra Front.
Around 212 fighters from Lebanon's Hezbollah movement, allied with the Syrian government, were also killed in the violence, according to the Britain-based Observatory, which relies on a network of activists inside war-torn Syria.
This year has seen the establishment of several de-escalation zones in Syria aimed at curbing violence in the country.
The zones were created by Turkey, a long-time backer of rebels, in conjunction with Russia and Iran, the two main supporters of Syrian President Bashar al-Assad.
The Observatory said it had documented 49,742 deaths in Syria's violence in 2016.
Syria's crisis began with peaceful anti-government demonstrations in March 2011.
The conflict soon spiralled into a multi-sided civil war that has claimed hundreds of thousands of lives and displaced about half of Syria's pre-war population of 22 million.
More than 494,000 people are estimated to have been killed in the conflict, according to the Observatory.
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Around 212 fighters from Lebanon's Hezbollah movement, allied with the Syrian government, were also killed in the violence, according to the Britain-based Observatory, which relies on a network of activists inside war-torn Syria.
This year has seen the establishment of several de-escalation zones in Syria aimed at curbing violence in the country.
The zones were created by Turkey, a long-time backer of rebels, in conjunction with Russia and Iran, the two main supporters of Syrian President Bashar al-Assad.
The Observatory said it had documented 49,742 deaths in Syria's violence in 2016.
Syria's crisis began with peaceful anti-government demonstrations in March 2011.
The conflict soon spiralled into a multi-sided civil war that has claimed hundreds of thousands of lives and displaced about half of Syria's pre-war population of 22 million.
More than 494,000 people are estimated to have been killed in the conflict, according to the Observatory.
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