At a press conference on Sunday, Guterres said that Syria's affected population must receive relief and that the Syrian transitional government should be supported in its efforts to find a future path for the country.
"I welcome the steps taken to ease sanctions and open up for economic reconstruction, but all sanctions must be lifted," Guterres said.
The World Bank estimates that $216 billion is needed to rebuild the country after more than 13 years of civil war.
Several leading countries, including the United States, have eased sanctions on Syria, but the UN chief thinks this is happening too slowly.
