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"The UN report documents the last three months in Syria, during which, the investigators say, the violence has reached new and terrible levels.

They have evidence that Syrian forces have shot dead women and children, subjected civilian areas to merciless shelling, and tortured wounded protestors in hospital.

These systematic violations were ordered by high ranking figures in the military and government, the report says."

"UK Foreign Secretary William Hague said the international community would be looking at further ways to apply pressure to Mr Assad.

"It is a deeply frustrating situation that people have been dying in their thousands... that the Assad regime has continued to act seemingly with impunity - but I think we can agree to a wider set of measures across a large group of nations," Mr Hague said.

The European Union sanctions on Syria could be tightened further, Mr Hague added."

"Russia and China have faced Western and Arab criticism for blocking a UN Security Council resolution that would have backed an Arab League peace plan for Syria.

Opposition groups claim more than 7,500 people have been killed since the start of the uprising 11 months ago."