The United Nations humanitarian chief Valerie Amos has made a brief visit to the Homs, describing parts of the Syrian city as "devastated."
Baroness Amos that Homs felt like a city that had been closed down entirely.
She spent less than an hour in the bombed-out Baba Amr district, assessing its humanitarian needs, before moving on to other districts of the city and then returning to Damascus.
Relief teams have been waiting since Friday to move into the district, but International Red Cross officials say most residents have already fled.
The government retook the district last week after fierce shelling.
The Red Crescent has not yet been able to deliver any aid to Baba Amr.
The rebel Free Syrian Army left Homs last week in the hope, it said, of protecting civilians from further violence.
The UN says more than 7,500 people have died as a result of the violence in Syria over the past 12 months.