GENEVA (Reuters) - Syrian government forces have committed human rights violations, including executions, across the country "on an alarming scale" during military operations in the past three months, United Nations investigators said on Wednesday.
Their report, presented by investigation head Paulo Pinheiro to the United Nations Human Rights Council in Geneva, also listed multiple killings and kidnappings by armed opposition groups trying to topple President Bashar al-Assad.
"In the increasingly militarised context, human rights violations are occuring across the country on an alarming scale during military operations against locations believed to be hosting defectors and/or those perceived as affiliated with anti-government armed groups, including the Free Syrian Army," the 20-page report said.
Syria's ambassador dismissed the accusations and walked out of the debate after threatening to end cooperation.
The investigation's report also said it was unable to determine who carried out a massacre of more than 100 people in Houla in late May but that forces loyal to Assad may have carried out many of the killings. This was based on its preliminary analysis of satellite images, videos and interviews with witnesses conducted either by telephone or Skype.
Karen AbuZayd, an American investigator, told a news conference that the team had testimonies indicating that some people in Syria were being "targeted" along sectarian lines.
"Certainly we have no information to go as far as to say that there was religious cleansing. But we've said it and many others have said it, it's increasingly looking like there is a sectarian aspect to what is going on in Syria," she said.
Government troops were using machine guns, artillery and tanks to assault restive areas, including the city of Homs. For their part the rebel forces were increasingly using improvised explosive devices, it said.
The U.N. investigators voiced concern that rebels were using children as medical porters, messengers and cooks, exposing them to risk of death and injury. Some had been going back and forth across the border with Turkey, they said.
Pinheiro, who made a first visit to Damascus at the weekend for talks with senior Syrian officials, presented the report to the U.N. Human Rights Council that set up the international inquiry last September.
The Brazilian expert had discussed the Houla investigation with Syrian authorities and believed that the team would be able to begin working inside Syria, he told the 47-member forum.
"We can't say things for which we do not have sufficient evidence. We are in good company because nobody knows exactly what happened in that crime scene," he told a news conference.
Syria's ambassador Faysal Khabbaz Hamoui rejected the accusations as being based on testimony from people fleeing justice and "tendentious media".
"All sides recognise now that the crisis is not attributable to peaceful demonstrations and legitimate demands for reform. The crisis in Syria is a genuine war," Khabbaz Hamoui said.
Russian diplomat Vassily Nebenzia, whose country is Assad's main defender, said that Syrian militants were carrying out daily attacks on infrastructure and killing civilians.
"Gunmen have been carrying out terrorist acts on Syrian cities. Such activities by gunmen and terrorists are being fed with money and weapons from abroad," he said.
Western powers called for Pinheiro's commission to be given "full and unfettered access" to Syria immediately.
"The evidence is incontrovertible. The Assad regime is waging a brutal campaign against the Syrian people, characterised by aerial bombardment, mass killings, rape and other atrocities," U.S. ambassador Eileen Chamberlain Donahoe said in her speech.
The U.N. team, which conducted nearly 400 interviews, said it had collected photographs, videos, satellite imagery and other documentary evidence during its recent investigative missions in the region.
It was updating its confidential list of identified perpetrators for possible use in future criminal prosecutions for war crimes and crimes against humanity.
"We provided a list of names and units of the military forces or security sections of the government of Syria that based on our evidence would be able to be investigated as being responsible for gross human rights violations and international crimes," Pinheiro said. (Reporting by Stephanie Nebehay; Editing by Angus MacSwan and Toby Chopra)