The Syrian army and security forces have been responsible for the majority of the serious rights abuses committed since March this year as they hunt down defectors and opponents, UN-appointed investigators said on Thursday.
"Most of the serious human rights violations documented by the Commission in this update were committed by the Syrian army and security services," said the Independent Commission of Inquiry on Syria, established by the UN Human Rights Council last year to investigate abuses there since the crackdown.
These violations were committed "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," it said.
The panel, which carried out 214 interviews since March but has not been granted access to Syria, said "a clear pattern" had emerged of government blockades of villages and neighbourhoods to "weed out" wanted people and their families.
"Children have died due to a lack of adequate health care during government blockades," said the commission.
"Some, including those injured as a result of torture, have been willfully denied medical care."
The panel also highlighted the "systematic denial" in some areas of access to food and water and restrictions on freedom of movement.
More than 12,600 people have been killed since March 2011 in a crackdown on dissidents by the government of President Bashar al-Assad, according to the Syrian Observatory for Human Rights.