World Food Program spokeswoman Elisabeth Byrs said the agency hoped to reach 4 million people in Syria by the end of the year, the U.N. News Center said in a statement.
However, WFP trucks had been unable to get into nearly 40 locations since mid-2012. In those areas "even the most basic items were in scarce supply," Byrs said.
The agency had tried nine times to enter the city of Moadamiyeh "and could not confirm what exactly was happening in that area," she said. Damascus and the surrounding area were among the hardest places to access, Byrs said, because of an ongoing siege in many areas.
Amnesty International says hundreds of people fleeing the conflict in Syria have been refused entry to refugee camps in neighboring countries, the BBC reported. The humanitarian organization said Palestinians and Iraqis who had been living in Syria, and people without identity documents, are among those being turned back.
More than 2 million people have fled Syria and sought refuge in Lebanon, Jordan, Turkey, Iraq and Egypt.
Jordanian government spokesman Mohammed al-Momani denied the allegations, saying there had been "no change" in the country's attitude toward refugees.
"Refugees that reach our borders are allowed in, in accordance with international law and Jordan's historical position of providing safety to those who seek it," he said.
AI called for refugees to be able to cross borders easily, but said countries hosting refugees need international support to cope with the flow.
The United Nations has appealed for $4.4 billion in donations, but has received only about half of that.