Damascus - United Nations humanitarian chief Valerie Amos said on Thursday as many as 2.5 million people were in need of aid in Syria, where President Bashar Assad's forces have been fighting rebels seeking his overthrow for 17 months.
Speaking in Syria where she met Prime Minister Wael al-Halki and other officials this week, Amos urged government forces and rebels to do more to protect civilians caught up in the violence.
"Over a million people have been uprooted and face destitution. Perhaps a million more have urgent humanitarian needs due to the widening impact of the crisis on the economy and people's livelihoods," she told reporters in Damascus.
"Back in March, we estimated that a million people were in need of help. Now as many as 2.5 million are in need of assistance and we are working to update our plans and funding requirements."
A United Nations appeal to raise $180m for Syria this year, based on earlier estimates of humanitarian needs, is only 40% funded so far, UN officials say.
Efforts to increase emergency aid have also been hindered by escalating violence, which has thwarted plans for regional humanitarian offices across Syria to deliver assistance, and by Syrian restrictions on aid groups operating on its territory.
Amos said she had met displaced families in Damascus and the town of Nabk northeast of the capital who were housed in public buildings and schools, which are due to reopen next month.
"Their needs for health care, shelter, food, water and sanitation are growing," Amos said. "The UN and its partners are reaching more people with emergency aid every month. But we are only meeting some of the needs."
"It's not enough. Insecurity and restrictions are part of the problem. But funding too is holding us back," she said, appealing for international donations to support the emergency effort.