Britain will continue to press for tougher United Nations authority to bypass obstructions to getting humanitarian aid to victims of Syria's civil war, William Hague said after the official estimate of the number now in need neared 11 million.
UN humanitarian chief Baroness Amos said the regime of Bashar Assad was more concerned with "controlling" the work of aid agencies than getting emergency supplies to victims of the fighting.
Damascus has warned any attempt to authorise aid being sent directly into rebel-held areas from neighbouring countries - a move under discussion as part of efforts to agree a new Security Council resolution - would justify retaliation.
A resolution passed four months ago has proved inadequate, with Baroness Amos revealing in her latest update that an additional 1.2 million have been added to those in need in that period, taking it to 10.8 million.
Mr Hague said: "The regime's failure to comply with UN Security Council demands has led to the rapid deterioration of the humanitarian situation in Syria with half of Syria's population now in need of humanitarian assistance."