UN humanitarian chief Valerie Amos has said parts of the Syrian city of Homs have been "completely devastated".
She said that it felt like the city had been closed down entirely.
Baroness Amos visited the city yesterday, briefly entering the bombed-out Baba Amr district.
Aid teams have waited days to go there, but aid officials said most residents had gone to areas already getting aid.
The government retook the district last week after fierce shelling.
Activists say troops committed massacres since they entered while Damascus blames rebels for many deaths.
International media organisations are heavily restricted in Syria, making it impossible to verify the claims of either side.