Reuters reports: Fighters from around the world have filtered into Syria to join a civil war that has split along sectarian lines, increasingly pitting the ruling Alawite community against the majority Sunni Muslims, U.N. human rights investigators said on Thursday.

The deepened sectarian divisions in Syria may diminish prospects for any post-conflict reconciliation even if President Bashar al-Assad is toppled. And the influx of foreign fighters raises the risk of the war spilling into neighboring countries, riven by the same sectarian fault lines that cut through Syria.

“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 investigators led by Brazilian expert Paulo Pinheiro said in an updated report.

As a result, they said, more civilians were seeking to arm themselves in the conflict, which began 21 months ago with street demonstrations demanding democratic reform and evolved into an armed insurgency bent on toppling Assad.

“What we found in the last few months is that the minorities that tried to stay away from the conflict have begun arming themselves to protect themselves,” Karen Abuzayd, a member of the group, told a news conference in Brussels.