The Syrian Network for Human Rights (SNHR) released a report on Monday stating that more than 21,000 people were killed in 2015 with 1,793 killed in December alone.
The London-based rights group said that this year’s death toll has reached 21,179, 75 percent of whom were killed by Syrian regime leader Bashar al Assad’s forces.
The rights group reported that 15,748 people were killed by regime forces, including 12,044 civilians and at least 2,592 of the victims were children, while 1,957 were women.
The report also showed that Russian forces killed 849 civilians, including 199 children and 109 women since September.
Meanwhile, Syrian Kurdish forces killed 132 civilians, including 32 children and 12 women.
The DAESH terrorist group killed 2,098 people, including 1,366 civilians, as the Al Qaeda-linked Nusra Front killed 167 people, including 89 civilians.
According to the report, Syrian opposition factions killed 1,121 people, 1,072 of whom were civilians.
The SNHR also recorded the killing of 787 individuals, including 631 civilians, by unidentified groups in Syria.
The United Nations also in a report highlighted that at least 250,000 people have been killed since the Syrian conflict began in 2011.