In the heart of rebel-held territory in Syria’s northern province of Aleppo, a small group of intrepid Westerners is undertaking a mission of great stealth. Living anonymously in a small rural community, they travel daily in unmarked cars, braving airstrikes, shelling and the threat of kidnapping to deliver food and other aid to needy Syrians — all of it paid for by the U.S. government.

So secretive is the operation, however, that almost none of the Syrians who receive the help are aware of its American origins. Out of concern for the safety of the recipients and the delivery staff, who could be targeted by the government if their affiliation to the United States were known, the Obama administration and the aid workers have chosen not to advertise the assistance…

“America has done nothing for us. Nothing at all,” said Mohammed Fouad Waisi, 50, spitting out the words for emphasis in his small Aleppo grocery store, which adjoins a bakery where he buys bread every day. The bakery is fully supplied with flour paid for by the United States. But Waisi credited Jabhat al-Nusra — a rebel group the United States has designated a terrorist organization because of its ties to al-Qaeda — with providing flour to the region, though he admitted he wasn’t sure where it comes from…

The unpublicized aid effort, which The Washington Post was invited to witness on the condition that it not identify the agency involved, the names or nationalities of its staff, or the precise locations in which the workers operate, illustrates the dilemma confronting the Obama administration as it cautiously explores ways of stepping up support for the Syrian opposition.