Syria’s civil war is increasingly turning into a sectarian conflict pitting majority Sunni rebels against government forces supported by the country’s religious and ethnic minorities, a new UN human rights report has said.

Sergio Pinheiro, a Brazilian expert who heads an independent commission investigating abuses, said on Thursday the bulk of the victims of the nearly two-year war were civilians, and blamed both sides for abuses including torture and illegal executions.

Activists say about 40,000 people have died on both sides since the conflict erupted in March 2011.

The report, commissioned by the UN Human Rights Council, found that foreign fighters, many linked to hardline Sunni groups, are infiltrating into Syria.

They are operating in independent units that coordinate actions with the Free Syrian Army – the Western-backed armed group that is the rebels’ main military force.

“The commission is extremely worried by the presence of foreign fighters … who are not fighting for human rights and democracy,” Pinheiro told reporters in Brussels. “By their own admission, they are very proud of their breaches of humanitarian law.”

Although Pinheiro visited Damascus, the panel was not allowed into Syria and was forced to compile its report – which covers September 28 to December 16 – from interviews with Syrians who have fled the conflict.

Hundreds of thousands of Syrians have escaped into Turkey, Jordan, Lebanon and Iraq.

Dividing lines

Pinheiro noted that anti-government rebels were hiding in Syrian cities where they were “failing to distinguish themselves” from the civilian population, triggering strikes by government artillery and the air force.

While the sectarian divide is sharpest between the Sunni and Alawi communities, from which most of the senior government and military leaders hail, other minority groups have been increasingly drawn into the conflict, the report said.

“As battles between government and anti-government armed groups approach the end of their second year, the conflict has become overtly sectarian in nature,” it said, adding that Christians, Armenians, Druze and others have largely aligned themselves with President Bashar al-Assad’s regime.

“The commission has received credible reports of anti-government groups attacking Alawis and other minority communities,” the report said.

Almost all of the 80,000 Christians who used to live in the central town of Homs, the scene of intense fighting between the warring sides, have fled to Damascus or Beirut, the report said.

Jabhat al-Nusra, the largest grouping of hardline foreign fighters in Syria, is said to have a significant presence in Homs.

Syria’s Kurds, who predominantly live in the northeast, have clashed with both government and anti-government armed groups over control of that territory, the report said.

But in recent months, as the Syrian army ceded control of the region, clashes between Kurds and opposition groups and foreign fighters have intensified.

“We think this is a war where no military victory is possible,” Pinheiro said. “It is a great illusion that providing arms to one side or the other will help end it.”