The new aid will "help meet the acute needs of people inside Syria and refugees across the region who are affected by the violence in Syria", Xinhua quoted State Department spokeswoman Victoria Nuland as saying in a statement.
The new funding includes the $10 million announced last week in Turkey by a visiting US delegation, she said.
The total US aid to Syria has now reached $365 million.
Last week, senior US officials, including Ambassador to Syria Robert Ford, visited camps for displaced Syrians in Turkey and held talks with Turkish officials.
During the visit, the delegation announced that Washington would give $10 million of aid to help supply daily food to 210,000 people in the northern Syrian city of Aleppo.