GENEVA - Syrian government forces and opposition fighters are committing gross human rights violations despite a six-week-old ceasefire in the conflict and children are often the victims, United Nations investigators said in a report on Thursday.Syrian army and security services committed most of the crimes documented since March, including heavy shelling of residential areas and executions, it said.Children were frequently among those killed and wounded during attacks on protests and the bombardment of towns and villages by state forces, it said.The team of investigators, lead by Brazilian expert Paulo Pinheiro, has not been allowed into Syria, but based their report on more than 200 interviews of victims and witnesses conducted in the region and Geneva.They were able to confirm 207 deaths during the two-month period. The United Nations is deploying up to 300 unarmed military observers in Syria to monitor an April 12 truce that has yet to take hold.Security forces used lethal force against demonstrations in Aleppo, Damascus, Deraa, Hama, Homs, Idlib and in numerous villages across the country since March, the report said."Other unlawful killings took place during government military operations undertaken to weed out defectors, anti-government armed groups, their families and other opponents perceived to be supporting anti-government armed groups."The UN panel said it had received multiple reports of the armed opposition executing members of the army and security forces, suspected informers and collaborators.It has already drawn up a secret list of Syrian officials suspected of ordering crimes against humanity and handed it over to UN rights chief Navi Pillay.She has said that the situation in Syria should be referred to the International Criminal Court (ICC) for prosecution.Armed rebels executed or tortured captured soldiers and pro-government supporters, and abducted civilians in an apparent bid to secure prison exchanges or ransoms, it said."Most of the serious human rights violations documented by the commission in this update were committed by the Syrian army and security services as part of military or search operations conducted in locations known for hosting defectors and/or armed persons, or perceived as supportive of anti-government armed groups," the report said.