BBC News with Iain Purdon

The United Nations Secretary General Ban Ki-moon says the Syrian authorities have committed clear and widespread crimes against the country's civilian population. He was addressing the UN General Assembly in New York. Earlier, the International Committee of the Red Cross said its aid

convoy

in the devastated city of Homs had been denied access to the devastated Baba Amr district. Mr Ban said there were grisly reports coming out of Syria.

"In Homs, Hama and elsewhere, the brutal fighting has

trapped

civilians in their homes without food, heat or electricity or medical care, without any chance of evacuating the wounded or burying the dead. People have been reduced to melting snow for drinking water. This

atrocious

assault is all the more

appalling

for having been waged by the government itself, systematically attacking its own people."

The blocking of the ICRC mission to Baba Amr comes amid growing accusations of human rights violations by the Syrian authorities, as Jim Muir reports.

The Red Cross convoy with seven lorry loads of emergency supplies and three ambulances had arrived in Homs from Damascus early in the day, but it spent hours waiting at the local Syrian Red Crescent headquarters for the go-ahead to move into Baba Amr as planned, only to find it wasn't allowed to move. The ICRC has suspended the planned operation for the night, but says it intends to continue pressing for access as soon as possible. It's clearly alarmed by reports from activist organisations of revenge killings and