DAMASCUS - Jihadists in Syria were accused on Friday of war crimes over the killing of 190 civilians from President Bashar al-Assad's Alawite minority, in the largest atrocity attributed to rebel fighters.
Human Rights Watch said another 200 people - the vast majority women and children - were taken hostage in the operations that took place in August and are still being carried out.
The report, which urged an arms embargo on groups suspected of war crimes or crimes against humanity, said at least 67 of the victims were "executed or unlawfully killed".
It comes as NATO chief Anders Fogh Rasmussen said he sees no military solution to the 31-month conflict in Syria, which has killed more than 115,000 people.
HRW said the killings began on August 4, the first day of the Eid Al-Fitr holiday ending the Muslim fasting month of Ramadan, in a sweep of villages in Latakia province, an Alawite stronghold.
"These abuses were not the actions of rogue fighters," said HRW's Joe Stork. "This operation was a coordinated, planned attack on the civilian population."
The 105-page report, based on interviews with 35 survivors, emergency personnel and fighters on both sides, said at least 20 groups were involved, but that five "are responsible for specific incidents that amount to war crimes".
It named them as Ahrar al-Sham, Islamic State of Iraq and the Levant (ISIL), Al-Nusra Front, Jaish al-Muhajireen Wal-Ansar and Suqur al-Ezz.
HRW said that, in some cases, opposition fighters executed or gunned down entire families, or killed the elderly or infirm who had been left behind by those who fled.
HRW also said "some of the opposition atrocities... had clear sectarian motivation".
In one village, it said fighters intentionally damaged an Alawite maqam, a site where a religious figure is buried, and "appear to have intentionally damaged and dug up the grave".
It said they had also abducted and executed Sheikh Bader Ghazzal, the area's Alawite religious leader, quoting Al-Nusra as saying he had been executed because he supported the regime.