The meeting on Wednesday came just a week before the so-called 'Geneva II' peace conference aimed at finding a political solution to the 34-month conflict that has claimed more than 130,000 lives and displaced millions of people.
"More than $2.4 billion has been pledged at the conference," UN secretary General Ban Ki-moon said at the conclusion of the meeting, attended by delegates from nearly 70 nations and 24 international organizations.
But the UN was appealing for $6.5 billion in what it said was the largest ever in its history for a single humanitarian emergency.
It is seeking $2.3 billion to support 9.3 million people inside Syria and $4.2 billion for refugees, expected to nearly double to 4.1 million in number by year's end.
Officials, human rights and aid groups have expressed dismay at the worsening situation.
Ban himself said "half of the total population of Syrian people, nearly 9.3 million individuals, urgently need humanitarian aid," pointing out that more than three million people have fled the country.
"I am especially concerned about reports of starvation" in Syria, he said.
EU Aid Commissioner Kristalina Georgieva said "we see the humanitarian situation going from bad to worse; we have seen no improvement."
And with fighting intense as ever and the prospects of a negotiated solution dim, rights and aid groups say urgent funds are needed.
On Tuesday, Amnesty International said "the continuing violence in Syria has sparked one of the biggest humanitarian crises in recent history.
"The world's response to the Syria crisis so far has been woefully inadequate," Amnesty said.
UN Emergency Relief Coordinator Valerie Amos said Wednesday that around 245,000 Syrians are living in towns and cities under siege and facing extreme hardships, including food shortages.
"I am deeply troubled by the persistent reports of people running out of food in those besieged communities, where some 245,000 people live," Amos said.
According to aid agencies, 10.5 million Syrians are food insecure, more than a million children under five suffer from acute or severe malnutrition, about half the population has no access to adequate water sources or sanitation and 8.6 million have insufficient access to healthcare.
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