Syrian President Bashar al-Assad's forces have killed some 2,900 people "with knives," the opposition National Coalition said in a new report Tuesday.
The publication, timed to coincide with International Human Rights Day, accuses Syrian government forces of carrying out "at least 20 massacres that involved the slaughter of 2,885 people" with knives and other crude weapons.
The victims, the report said, include "more than 200 children and 120 women."
The Coalition said the killings amounted to "a series of organised crimes of genocide."
It said the 81-page report was based on open source reporting, investigations by international organisations and the testimony of both survivors and opposition activists.
Among the incidents documented in the report are the deaths of at least 110 people in the town of Houla in central Homs province on May 25, 2012.
The United Nations concluded that the majority of those killed in the incident were summarily executed, and local residents said the attack was carried out by pro-regime militias.
The report also noted dozens of deaths in the city of Banias and the village of Bayda nearly a year later, many of them summary executions of women and children.
"The regime began in the early days of the revolution to establish death squads specifically to carry out massacres with 'cold arms,'" the Coalition said, using a term for weapons that do not use fire or explosions.
More than 125,000 people have been killed in 33 months of fighting in Syria between anti-government forces and the regime, according to the Syrian Observatory for Human Rights, a Britain-based group that relies on activists and other witnesses on the ground.