Syria has agreed to allow a survey of the basic medical needs of people in four cities that have been ravaged in the regime's crackdown on opposition forces, according to UN officials.
Valerie Amos said on Friday the Syrian government would permit the assessment of locals' relief needs in areas hit badly by the conflict.
However, the UN agencies for health and population will have to depend on the help of local medical students, Syrian Red Crescent workers and other non-governmental organizations to carry out the survey.
Amos also said that Damascus must allow aid workers "unhindered access to the wounded and deliver desperately needed supplies."
The aid chief said she was "horrified by the destruction" she saw when she visited the embattled Baba Amr neighborhood of Homs on Wednesday. The former rebel stronghold was bombarded for a month by government forces, which stormed and retook it last week. Amos said hardly any people left there during her visit.
Some 1.5 million people may be in need of food aid in the country, a UN spokeswoman for the office for the Coordination of Humanitarian Affairs, told reporters in Geneva on Friday.
EU praises sanctions
At a meeting in Copenhagen on Friday, European Union foreign ministers said that sanctions against the regime of Bashar al-Assad were working, pointing to defections from high-level government officials as proof.
German Foreign Minister Guido Westerwelle said the regime was in an increasing "state of dissolution."
"We must be patient," said Luxembourg's foreign minister, Jean Asselborn. "We will unfortunately have to accept to see enormously more victims, but military intervention would be worse."
Turkish officials said on Friday that several senior Syrian military officers had defected to Turkey on Thursday, the same day a video was released of Syria's deputy oil minister saying he was joining the opposition.
Opposition rejects call for dialogue
UN envoy Kofi Annan is due to travel to Damascus on Saturday and has called for talks between the government and rebels to put an end to the year-long conflict.
The UN says that over 7,500 people have been killed in Syria since the conflict began.
ncy/sjt (Reuters, AFP, AP, dpa)