International donors have pledged $4.4 billion in humanitarian aid for Syria and neighboring countries that have sheltered refugees this year.
But the pledge total is significantly less than the more than $7 billion the United Nations is seeking.
Mark Lowcock, head of the U.N. Office for the Coordination of Humanitarian Affairs, said Wednesday that the pledges made an at international donor conference in Brussels were a "good start." He said that based on previous years' results, he expected more money would come in.
WATCH: Syrian War Produces More Refugees as Aid Funds Fall Short
Lowcock said several major donors, including the United States, had not yet confirmed their pledges. He said the United States has been providing more than $1 billion a year to Syria and the region in recent years.
Lowcock said the additional money for 2019 was needed for humanitarian purposes in Syria and to assist refugees in nearby countries.
"The key issue is to make sure ... priority is given to those in most need and those most vulnerable," said Lowcock, noting that Britain and Germany had made the largest pledges.
About 450,000 people have been killed in Syria since President Bashar al-Assad's in 2011 began cracking down on protesters calling for his ouster.
The United Nations says more than 13 million Syrians need humanitarian aid and about one-fourth of them have been displaced in neighboring countries such as Jordan, Lebanon and Turkey.
The United Nations says more than 700,000 people have been displaced this year as Assad has escalated attacks against rebel forces, intensifying the humanitarian crisis.
The European Union, which hosted the conference, had hoped the meeting of more than 80 countries, aid organizations and agencies would stimulate stalled U.N. peace initiatives, in addition to raising humanitarian aid.
Meanwhile, an international chemical weapons monitoring group said a team of inspectors collected samples Wednesday at a second site where an alleged gas attack occurred more than two weeks ago in Douma, Syria.
The team from the Organization for the Prohibition of Chemical Weapons collected its first samples Saturday at another site in Douma.
The OPCW said a report based on the findings and other information gathered by the team would be drafted after designated laboratories analyzed the samples.