United Nations envoy Kofi Annan has told the Security Council he is very concerned by reports that Syrians who speak to UN observers are being harassed and even killed by pro-government forces.
Mr Annan has been briefing the UN Securtity Council in private on his efforts to mediate in the Syrian crisis, the BBC reports.
Activists said 70 people were killed on Monday, mostly in the city of Hama.
Diplomats have reported Mr Annan as telling the UN that the overall situation was entirely contrary to the will of the international community.
Earlier Mr Annan's spokesman, Ahmed Fawzi, said satellite imagery showed the Syrian government was failing to withdraw heavy weapons from urban centres.
He said there were credible reports that people who met monitors were then approached and sometimes killed by security forces.
Meanwhile, the UN says it aims to deliver food aid to 500,000 people in Syria in the coming weeks.
In a statement, the UN's World Food Programme concedes it faces challenges in delivering the food but says it is increasing its assistance at the request of the Syrian Arab Red Crescent .
UN aid agencies have been largely prevented from operating in the country but a joint assessment mission with the Syrian authorities last month estimated at least 1 million people need humanitarian aid.