Violence in the Syria conflict has become openly sectarian and threatens whole communities, UN investigators reported Thursday following a visit to the region.
"As battles between government forces and anti-government armed groups approach the end of their second year, the conflict has become overtly sectarian in nature," the UN Commission of Inquiry on Syria said in a report.
After 21 months of the conflict, which activists say has killed more than 43,000 people, "the dangers are evident," it continued. It cited in particular tensions between Sunnis and Shiites.
"Entire communities are at risk of being forced out of the country or of being killed inside the country," it said, stressing that "with communities believing -- not without cause -- that they face an existential threat, the need for a negotiated settlement is more urgent than ever."
Minority groups such as the Armenians, Christians, Druze, Palestinians, Kurds and Turkmen had also been drawn into the conflict, the report said.
Caught up in the cycle of attacks and reprisals, they were being forced to choose sides and allow themselves to be armed by the warring parties.
"However, the sectarian lines fall most sharply between Syria's Alawite community, from which most of the government's senior political and military figures hail, and the country's majority Sunni community, who are broadly... in support of the anti-government armed groups."
The commission said it had received "credible reports" of anti-government groups attacking Alawites; and one account of how rebels who had captured government troops took the Sunnis hostage but executed the Alawites.
Another interviewee in Bosra had told the commission how Shia militia members had said they would kill all Sunnis in the region.
The UN commission, which includes former war crimes prosecutor Carla del Ponte, was set up in August 2011, but has yet to actually gain access to Syria.
It did however travel to Jordan and Egypt earlier this month to review the situation, and had previously conducted more than 1,000 interviews. They talked not just to victims of the conflict but to people who admitted to having taken part in the violence.
Those interviews led the commission to conclude last August that both the regime and rebel forces appeared to be committing war crimes.