The UN Security Council is demanding immediate access to Syria for its humanitarian chief, Valerie Amos.
Russia and China, who vetoed two previous Security Council resolutions on Syria, are also backing the call for Baroness Amos to be allowed in.
It comes as the rebel Free Syrian Army said it was withdrawing from the Baba Amr district of Homs, which has been under siege for nearly a month.
France says two French journalists trapped in Homs are now safely out.
Earlier, the International Committee of the Red Cross said it and the Syrian Red Crescent had been given the green light to go to Baba Amr today to deliver food and medical supplies.